/* ============================================================
   simulator.css — Shell & layout for ALL simulators
   Edit here → updates every simulator automatically.
   engsim.app
   ============================================================ */

/* ══════════════════════════════════════════════════════════════
   REQUIRED PATTERN FOR ANY NEW NAMESPACED SLIDER
   Copy this block. Do not use accent-color for tracks. Unfilled track is var(--border-strong), thumb is var(--slider-color, var(--brand-accent)) with no border/shadow, scale(1.15) on hover.
   ══════════════════════════════════════════════════════════════
.sim-namespace input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    background: transparent;
}
.sim-namespace input[type="range"]::-webkit-slider-runnable-track {
    background: var(--border-strong);
}
.sim-namespace input[type="range"]::-moz-range-track {
    background: var(--border-strong);
}
.sim-namespace input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    background: var(--slider-color, var(--brand-accent));
    box-shadow: none;
    border: none;
    transform: scale(1);
    transition: transform 0.2s;
}
.sim-namespace input[type="range"]::-moz-range-thumb {
    background: var(--slider-color, var(--brand-accent));
    box-shadow: none;
    border: none;
    transform: scale(1);
    transition: transform 0.2s;
}
.sim-namespace input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.15);
}
.sim-namespace input[type="range"]::-moz-range-thumb:hover {
    transform: scale(1.15);
}
*/

/* ══════════════════════════════════════════════════════════════
   SIM HERO — breadcrumb + title + tags
   ══════════════════════════════════════════════════════════════ */
.sim-hero {
    background: linear-gradient(135deg, #f0f4ff 0%, #e8effe 100%);
    border-bottom: 1px solid var(--border);
    padding: var(--space-xl) 0 var(--space-lg);
}

body.dark .sim-hero {
    background: linear-gradient(135deg, #1a2744 0%, #1e293b 100%);
}

.sim-hero__breadcrumb {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    font-size: .8rem;
    color: var(--text-muted);
    margin-bottom: var(--space-md);
    flex-wrap: wrap;
}

.sim-hero__breadcrumb a {
    color: var(--brand-accent);
    text-decoration: none;
}

.sim-hero__breadcrumb a:hover {
    text-decoration: underline;
}

.sim-hero__breadcrumb span {
    color: var(--text-muted);
}

.sim-hero__category {
    display: inline-block;
    font-size: .7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: .08em;
    color: var(--brand-accent);
    background: rgba(37, 99, 235, .1);
    padding: 3px 10px;
    border-radius: 99px;
    margin-bottom: var(--space-md);
}

.sim-hero__title {
    font-size: clamp(1.5rem, 4vw, 2.25rem);
    font-weight: 800;
    color: var(--text-primary);
    margin-bottom: var(--space-sm);
    line-height: 1.2;
}

.sim-hero__subtitle {
    font-size: 1rem;
    color: var(--text-secondary);
    max-width: 640px;
    line-height: 1.65;
    margin-bottom: var(--space-lg);
}

.sim-hero__tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-sm);
}

.sim-hero__tag {
    font-size: .75rem;
    color: var(--text-secondary);
    background: var(--bg-card);
    border: 1px solid var(--border);
    padding: 4px 12px;
    border-radius: 99px;
    font-weight: 500;
}

/* ══════════════════════════════════════════════════════════════
   SIM BODY — two-panel layout (sidebar + main)
   ══════════════════════════════════════════════════════════════ */
.sim-body {
    padding: var(--space-xl) 0;
}

/* Two-panel layout */
.sim-layout {
    display: grid;
    grid-template-columns: var(--sim-sidebar-width, 320px) 1fr;
    gap: var(--space-lg);
    align-items: start;
}

.sim-layout--full {
    display: block;
}

@media (max-width: 900px) {
    .sim-layout {
        grid-template-columns: 1fr;
    }
}

/* ── Panel / Card ───────────────────────────────────────────── */
.sim-panel {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
}

.sim-panel+.sim-panel {
    margin-top: var(--space-md);
}

.sim-panel__header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-md) var(--space-lg);
    border-bottom: 1px solid var(--border);
}

.sim-panel__title {
    font-size: .8rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .07em;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.sim-panel__title svg {
    width: 16px;
    height: 16px;
    color: var(--brand-accent);
    flex-shrink: 0;
}

.sim-panel__badge {
    font-size: .7rem;
    font-weight: 600;
    color: var(--text-muted);
    background: var(--bg-hover);
    padding: 3px 8px;
    border-radius: 99px;
}

.sim-panel__body {
    padding: var(--space-lg);
}

/* ── Form elements ──────────────────────────────────────────── */
.sim-field {
    margin-bottom: var(--space-md);
}

.sim-field:last-child {
    margin-bottom: 0;
}

.sim-label {
    display: block;
    font-size: .8rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--space-xs);
}

.sim-label-hint {
    font-size: .75rem;
    font-weight: 400;
    color: var(--text-muted);
    margin-left: var(--space-xs);
}

.sim-input-wrap {
    display: flex;
    align-items: center;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    background: var(--bg-input);
    transition: border-color var(--transition), box-shadow var(--transition);
    overflow: hidden;
}

.sim-input-wrap:focus-within {
    border-color: var(--brand-accent);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, .12);
}

.sim-input {
    flex: 1;
    border: none;
    background: transparent;
    padding: 9px 12px;
    font-size: .9rem;
    color: var(--text-primary);
    outline: none;
    min-width: 0;
}

.sim-input::placeholder {
    color: var(--text-muted);
}

.sim-unit {
    padding: 0 12px;
    font-size: .8rem;
    color: var(--text-muted);
    background: var(--bg-hover);
    border-left: 1px solid var(--border);
    align-self: stretch;
    display: flex;
    align-items: center;
    flex-shrink: 0;
    font-family: var(--font-mono);
}

.sim-hint {
    font-size: .73rem;
    color: var(--text-muted);
    margin-top: var(--space-xs);
}

.sim-select {
    width: 100%;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    background: var(--bg-input);
    padding: 9px 12px;
    font-size: .9rem;
    color: var(--text-primary);
    outline: none;
    cursor: pointer;
    transition: border-color var(--transition);
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2394a3b8' stroke-width='2'%3E%3Cpolyline points='6 9 12 15 18 9'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
    padding-right: 36px;
}

.sim-select:focus {
    border-color: var(--brand-accent);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, .12);
}

.sim-grid-2 {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-md);
}

.sim-grid-3 {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: var(--space-md);
}

@media (max-width: 480px) {

    .sim-grid-2,
    .sim-grid-3 {
        grid-template-columns: 1fr;
    }
}

.sim-section-label {
    font-size: .7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .08em;
    color: var(--text-muted);
    margin: var(--space-lg) 0 var(--space-md);
    padding-bottom: var(--space-xs);
    border-bottom: 1px solid var(--border);
}

.sim-section-label:first-child {
    margin-top: 0;
}

/* ── Buttons ─────────────────────────────────────────────────── */
.btn-primary {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    width: 100%;
    padding: 11px var(--space-lg);
    background: var(--brand-accent);
    color: #fff;
    font-size: .9rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    border: none;
    cursor: pointer;
    transition: background var(--transition), transform var(--transition);
    margin-top: var(--space-lg);
}

.btn-primary:hover {
    background: var(--brand-accent-h);
}

.btn-primary:active {
    transform: scale(.98);
}

.btn-primary svg {
    width: 16px;
    height: 16px;
    flex-shrink: 0;
}

.btn-secondary {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    padding: 7px 14px;
    background: var(--bg-hover);
    color: var(--text-secondary);
    font-size: .8rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    border: 1px solid var(--border);
    cursor: pointer;
    transition: background var(--transition), color var(--transition);
}

.btn-secondary:hover {
    background: var(--border);
    color: var(--text-primary);
}

/* ── Result cards ───────────────────────────────────────────── */
.sim-results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: var(--space-md);
    margin-bottom: var(--space-lg);
}

.sim-result-card {
    background: var(--bg-hover);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: var(--space-md);
    text-align: center;
}

.sim-result-card--accent {
    background: rgba(37, 99, 235, .06);
    border-color: rgba(37, 99, 235, .2);
}

.sim-result-label {
    font-size: .7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .07em;
    color: var(--text-muted);
    margin-bottom: var(--space-xs);
}

.sim-result-value {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--brand-accent);
    font-family: var(--font-mono);
    line-height: 1.1;
}

.sim-result-unit {
    font-size: .75rem;
    color: var(--text-muted);
    margin-top: 2px;
}

/* ── Error / alert ──────────────────────────────────────────── */
.sim-error {
    display: none;
    background: rgba(220, 38, 38, .08);
    border: 1px solid rgba(220, 38, 38, .25);
    border-radius: var(--radius-md);
    padding: var(--space-md);
    color: var(--color-danger);
    font-size: .875rem;
    margin-bottom: var(--space-md);
}

.sim-error.is-visible {
    display: block;
}

/* ── Canvas / chart containers ──────────────────────────────── */
.sim-chart-wrap {
    position: relative;
    background: var(--bg-hover);
    border-radius: var(--radius-md);
    overflow: hidden;
    margin-top: var(--space-md);
}

.sim-chart-label {
    font-size: .75rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: .05em;
    margin-bottom: var(--space-xs);
}

/* ══════════════════════════════════════════════════════════════
   EDUCATIONAL CONTENT — below the simulator
   ══════════════════════════════════════════════════════════════ */
.edu-content {
    padding: var(--space-2xl) 0;
    border-top: 1px solid var(--border);
    margin-top: var(--space-xl);
}

.edu-section {
    margin-bottom: var(--space-2xl);
}

.edu-section:last-child {
    margin-bottom: 0;
}

.edu-section h2 {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--space-md);
    padding-bottom: var(--space-sm);
    border-bottom: 2px solid var(--brand-accent);
    display: inline-block;
}

.edu-section h3 {
    font-size: 1rem;
    font-weight: 700;
    color: var(--text-primary);
    margin: var(--space-lg) 0 var(--space-sm);
}

.edu-section p {
    margin-bottom: var(--space-md);
}

.edu-section ul,
.edu-section ol {
    padding-left: var(--space-lg);
    color: var(--text-secondary);
    margin-bottom: var(--space-md);
}

.edu-section ul {
    list-style: disc;
}

.edu-section ol {
    list-style: decimal;
}

.edu-section li {
    margin-bottom: var(--space-xs);
    line-height: 1.65;
}

.edu-section hr {
    border: none;
    border-top: 1px solid var(--border);
    margin: var(--space-xl) 0;
}

/* FAQ */
.edu-faq {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.edu-faq-item {
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    overflow: hidden;
}

.edu-faq-item summary {
    font-weight: 600;
    font-size: .9rem;
    color: var(--text-primary);
    padding: var(--space-md) var(--space-lg);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    list-style: none;
    background: var(--bg-card);
    transition: background var(--transition);
}

.edu-faq-item summary:hover {
    background: var(--bg-hover);
}

.edu-faq-item summary::after {
    content: '+';
    font-size: 1.2rem;
    color: var(--text-muted);
    flex-shrink: 0;
}

.edu-faq-item[open] summary::after {
    content: '−';
}

.edu-faq-item .edu-faq-answer {
    padding: var(--space-md) var(--space-lg);
    background: var(--bg-hover);
    border-top: 1px solid var(--border);
    color: var(--text-secondary);
    font-size: .9rem;
    line-height: 1.7;
}

/* ══════════════════════════════════════════════════════════════
   EDU CONTENT — extra components (grid, formula, table, example)
   Used by educational sections across simulators.
   ══════════════════════════════════════════════════════════════ */
.edu-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: var(--space-md);
    margin: var(--space-md) 0 var(--space-lg);
}

.edu-grid-item {
    background: var(--bg-hover);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: var(--space-md);
}

.edu-grid-item h4 {
    font-size: .9rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--space-xs);
}

.edu-grid-item p {
    font-size: .85rem;
    margin-bottom: 0;
}

.edu-formula {
    display: block;
    font-family: var(--font-mono);
    font-size: .9rem;
    color: var(--text-primary);
    background: var(--bg-hover);
    border: 1px solid var(--border);
    padding: var(--space-sm) var(--space-md);
    border-radius: var(--radius-md);
    margin: var(--space-sm) 0;
    overflow-x: auto;
}

.edu-process-badge {
    display: inline-block;
    font-size: .7rem;
    font-weight: 700;
    color: var(--brand-accent);
    background: rgba(37, 99, 235, .1);
    padding: 2px 10px;
    border-radius: 99px;
    margin-left: var(--space-sm);
    vertical-align: middle;
}

.edu-table {
    width: 100%;
    border-collapse: collapse;
    margin: var(--space-md) 0;
    font-size: .85rem;
}

.edu-table th,
.edu-table td {
    text-align: left;
    padding: var(--space-sm) var(--space-md);
    border: 1px solid var(--border);
    vertical-align: top;
}

.edu-table th {
    background: var(--bg-hover);
    font-weight: 700;
    color: var(--text-primary);
}

.edu-table tbody tr:nth-child(even) {
    background: var(--bg-hover);
}

@media (max-width: 640px) {
    .edu-table {
        display: block;
        overflow-x: auto;
        white-space: nowrap;
    }
}

.edu-example {
    background: var(--bg-hover);
    border: 1px solid var(--border);
    border-left: 4px solid var(--brand-accent);
    border-radius: var(--radius-md);
    padding: var(--space-lg);
    margin: var(--space-md) 0;
}

.edu-example__title {
    font-weight: 700;
    color: var(--brand-accent);
    margin-bottom: var(--space-md);
    font-size: .95rem;
    text-transform: uppercase;
    letter-spacing: .03em;
}

.edu-example p {
    margin-bottom: var(--space-sm);
}

/* ══════════════════════════════════════════════════════════════
   CONDITIONAL FIELD VISIBILITY
   ══════════════════════════════════════════════════════════════ */
.is-hidden {
    display: none !important;
}

/* ══════════════════════════════════════════════════════════════
   INVALID INPUT — shake animation
   ══════════════════════════════════════════════════════════════ */
.sim-input-wrap.sim-input--invalid {
    border-color: var(--color-danger);
    box-shadow: 0 0 0 3px rgba(220, 38, 38, .15);
    animation: sim-shake .4s ease-in-out;
}

@keyframes sim-shake {

    0%,
    100% {
        transform: translateX(0);
    }

    20% {
        transform: translateX(-6px);
    }

    40% {
        transform: translateX(6px);
    }

    60% {
        transform: translateX(-4px);
    }

    80% {
        transform: translateX(4px);
    }
}

/* ══════════════════════════════════════════════════════════════
   STATUS BANNER
   ══════════════════════════════════════════════════════════════ */
.status-banner {
    display: flex;
    flex-direction: column;
    gap: 4px;
    padding: var(--space-md);
    border-radius: var(--radius-md);
    border: 1px solid transparent;
    margin: var(--space-md) 0;
    font-size: .875rem;
}

.status-banner__title {
    font-weight: 700;
    font-size: .9rem;
}

.status-banner__message {
    color: var(--text-secondary);
}

.status-banner--success {
    background: rgba(22, 163, 74, .08);
    border-color: rgba(22, 163, 74, .25);
}

.status-banner--success .status-banner__title {
    color: var(--color-success);
}

.status-banner--warning {
    background: rgba(217, 119, 6, .08);
    border-color: rgba(217, 119, 6, .25);
}

.status-banner--warning .status-banner__title {
    color: var(--color-warning);
}

.status-banner--danger {
    background: rgba(220, 38, 38, .08);
    border-color: rgba(220, 38, 38, .25);
}

.status-banner--danger .status-banner__title {
    color: var(--color-danger);
}

.status-banner--info {
    background: rgba(37, 99, 235, .06);
    border-color: rgba(37, 99, 235, .2);
}

.status-banner--info .status-banner__title {
    color: var(--brand-accent);
}

/* ══════════════════════════════════════════════════════════════
   ADVANCED PARAMETERS (collapsible)
   ══════════════════════════════════════════════════════════════ */
.sim-advanced {
    margin-top: var(--space-lg);
    border-top: 1px solid var(--border);
    padding-top: var(--space-sm);
}

.sim-advanced>summary {
    cursor: pointer;
    font-size: .8rem;
    font-weight: 600;
    color: var(--text-secondary);
    list-style: none;
}

.sim-advanced>summary::-webkit-details-marker {
    display: none;
}

.sim-advanced>summary::before {
    content: '▸ ';
}

.sim-advanced[open]>summary::before {
    content: '▾ ';
}

.sim-advanced-body {
    margin-top: var(--space-md);
}

/* ══════════════════════════════════════════════════════════════
   CHART WRAP — inner padding
   ══════════════════════════════════════════════════════════════ */
.sim-chart-wrap {
    padding: var(--space-md);
}

.sim-chart-wrap canvas {
    max-height: 260px;
}

.sim-grid-2>.sim-field,
.sim-grid-3>.sim-field {
    min-width: 0;
}

.sim-input-wrap {
    min-width: 0;
}


/* ════════════════════════════════════════════════════════════════
   T–S DIAGRAM (WATER) — namespace "ts-"
   Component-specific styles for the Temperature–Entropy simulator.
   Does not use the generic .sim-* system above; kept isolated under
   its own "ts-" prefix so it can't collide with other simulators.
   ════════════════════════════════════════════════════════════════ */
.ts-shell {
    --ts-primary: var(--brand-accent);
    --ts-accent: var(--color-danger);
    --ts-bg-panel: var(--bg-card);
    --ts-border: var(--border);
    --ts-text: var(--text-primary);
    --ts-text-muted: var(--text-secondary);
}

.ts-shell {
    display: grid;
    grid-template-columns: 350px 1fr;
    gap: 1.5rem;
    margin-top: 1rem;
}

@media (max-width: 1024px) {
    .ts-shell {
        grid-template-columns: 1fr;
    }
}

.ts-panel {
    background: var(--ts-bg-panel);
    border: 1px solid var(--ts-border);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.ts-panel__header {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 1.5rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--ts-border);
}

.ts-panel__title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--ts-text);
    margin: 0;
}

.ts-field {
    margin-bottom: 1.25rem;
}

.ts-label {
    display: block;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--ts-text-muted);
    margin-bottom: 0.5rem;
}

.ts-input-group {
    display: flex;
    align-items: center;
    gap: 10px;
}

.ts-input-number {
    width: 80px;
    padding: 0.5rem;
    border: 1px solid var(--ts-border);
    border-radius: 6px;
    background: var(--bg-input);
    color: var(--ts-text);
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.9rem;
}

.ts-slider {
    flex: 1;
    -webkit-appearance: none;
    appearance: none;
    height: 6px;
    border-radius: 3px;
    background: var(--border-strong);
    outline: none;
    padding: 10px 0;
    background-clip: content-box;
}

/* Restore keyboard focus ring (outline:none suppresses the browser default).
   :focus-visible fires only for keyboard navigation — no visual change on
   mouse/touch interaction. */
.ts-slider:focus-visible {
    outline: 2px solid var(--ts-primary);
    outline-offset: 4px;
    border-radius: 4px;
}

.ts-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--ts-primary);
    cursor: pointer;
    transition: transform 0.1s;
}

.ts-slider::-moz-range-thumb {
    width: 18px;
    height: 18px;
    border: none;
    border-radius: 50%;
    background: var(--ts-primary);
    cursor: pointer;
    transition: transform 0.1s;
}

.ts-slider::-webkit-slider-thumb:hover {
    transform: scale(1.1);
}

.ts-results {
    margin-top: 1.5rem;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
}

.ts-card {
    background: var(--bg-hover);
    border: 1px solid var(--ts-border);
    border-radius: 8px;
    padding: 0.75rem;
    text-align: center;
}

.ts-card__label {
    display: block;
    font-size: 0.7rem;
    text-transform: uppercase;
    color: var(--ts-text-muted);
    letter-spacing: 0.025em;
    margin-bottom: 4px;
}

.ts-card__value {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--ts-primary);
}

.ts-card__unit {
    font-size: 0.75rem;
    font-weight: 400;
    color: var(--ts-text-muted);
    margin-left: 2px;
}

.ts-process-box {
    margin-top: 1.5rem;
    padding-top: 1rem;
    border-top: 1px dashed var(--ts-border);
}

.ts-checkbox-group {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
}

.ts-checkbox-group input[type="checkbox"] {
    width: 16px;
    height: 16px;
    cursor: pointer;
}

.ts-select {
    width: 100%;
    padding: 0.5rem;
    border: 1px solid var(--ts-border);
    border-radius: 6px;
    background-color: var(--bg-input);
    font-size: 0.85rem;
    color: var(--ts-text);
    outline: none;
    cursor: pointer;
}

.ts-select:focus {
    border-color: var(--ts-primary);
}

.ts-region-badge {
    grid-column: span 2;
    padding: 0.5rem;
    background: rgba(37, 99, 235, .1);
    color: var(--ts-primary);
    border-radius: 6px;
    font-weight: 600;
    font-size: 0.9rem;
    text-align: center;
    border: 1px solid rgba(37, 99, 235, .25);
    transition: all 0.2s ease;
}

.ts-quality-bar {
    width: 100%;
    height: 8px;
    background: var(--border);
    border-radius: 4px;
    overflow: hidden;
    position: relative;
}

.ts-quality-bar__fill {
    height: 100%;
    background: var(--ts-primary);
    width: 0%;
    transition: width 0.1s ease-out;
}

.ts-didactic {
    margin-top: 1.5rem;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-left: 4px solid var(--ts-primary);
    border-radius: 8px;
    padding: 1rem;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
}

.ts-didactic__header {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--ts-primary);
    margin-bottom: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.ts-didactic__explanation {
    font-size: 0.85rem;
    color: var(--ts-text-muted);
    margin-bottom: 1rem;
}

.ts-formula {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.95rem;
    color: var(--ts-text);
    padding: 0.5rem;
    background: var(--bg-hover);
    border-radius: 6px;
    margin-bottom: 0.5rem;
    overflow-x: auto;
}

.ts-formula--values {
    font-size: 0.9rem;
    color: var(--ts-text-muted);
    border-left: 2px dashed var(--border-strong);
}

.ts-formula--result {
    font-weight: 700;
    color: var(--ts-primary);
    background: rgba(37, 99, 235, .1);
    border: 1px solid rgba(37, 99, 235, .25);
}

.ts-chart-container {
    background: var(--bg-card);
    border: 1px solid var(--ts-border);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    min-height: 500px;
    display: flex;
    flex-direction: column;
}

.ts-chart-header {
    margin-bottom: 1rem;
}

.ts-chart-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--ts-text);
}

.ts-canvas-wrap {
    flex: 1;
    position: relative;
    max-height: 550px;
}

/* Mobile responsive adjustments */
@media (max-width: 640px) {

    .ts-panel,
    .ts-chart-container {
        padding: 1rem;
        border-radius: 10px;
    }

    .ts-chart-container {
        min-height: 340px;
    }

    .ts-canvas-wrap {
        max-height: 380px;
    }

    .ts-input-number {
        width: 68px;
        font-size: 0.85rem;
    }

    .ts-slider::-webkit-slider-thumb {
        width: 22px;
        height: 22px;
    }

    .ts-slider::-moz-range-thumb {
        width: 22px;
        height: 22px;
    }

    .ts-results {
        gap: 8px;
    }

    .ts-card__value {
        font-size: 1rem;
    }

    .ts-formula {
        font-size: 0.85rem;
    }
}

/* ════════════════════════════════════════════════════════════════
   DC CIRCUIT ANALYZER — namespace "dcc-"
   Component-specific styles for the DC Circuit Analyzer simulator.
   Does not use the generic .sim-* system beyond composition; kept
   isolated under its own "dcc-" prefix so it can't collide with
   other simulators.
   ════════════════════════════════════════════════════════════════ */

.dcc-slider-row {
    display: grid;
    grid-template-columns: 1fr 90px;
    gap: var(--space-sm);
    align-items: center;
}

.dcc-slider-row--unit {
    grid-template-columns: 1fr 80px 74px;
}

@media (max-width: 480px) {
    .dcc-slider-row--unit {
        grid-template-columns: 1fr;
    }
}

.dcc-slider {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 6px;
    border-radius: 3px;
    background: var(--border-strong);
    outline: none;
    cursor: pointer;
}

.dcc-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--brand-accent);
    cursor: pointer;
    transition: transform .1s;
}

.dcc-slider::-webkit-slider-thumb:hover {
    transform: scale(1.1);
}

.dcc-slider::-moz-range-thumb {
    width: 16px;
    height: 16px;
    border: none;
    border-radius: 50%;
    background: var(--brand-accent);
    cursor: pointer;
}

.dcc-unit-select {
    padding: 9px 28px 9px 10px;
    font-size: .8rem;
}

.dcc-checkbox-label {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    font-size: .8rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-top: var(--space-md);
    cursor: pointer;
}

.dcc-checkbox-label input[type="checkbox"] {
    width: 16px;
    height: 16px;
    cursor: pointer;
}

.dcc-method-explain {
    margin-top: var(--space-md);
    padding: var(--space-sm) var(--space-md);
    background: rgba(37, 99, 235, .06);
    border: 1px solid rgba(37, 99, 235, .2);
    border-radius: var(--radius-md);
    font-size: .8rem;
    color: var(--text-secondary);
}

.dcc-method-explain strong {
    display: block;
    font-size: .75rem;
    text-transform: uppercase;
    letter-spacing: .05em;
    color: var(--brand-accent);
    margin-bottom: 4px;
}

.dcc-canvas-wrap {
    padding: var(--space-md);
}

.dcc-canvas-wrap canvas {
    width: 100%;
    max-width: 800px;
    height: auto;
    display: block;
    margin: 0 auto;
}

.dcc-analysis-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-lg);
    margin-top: var(--space-md);
}

@media (max-width: 900px) {
    .dcc-analysis-grid {
        grid-template-columns: 1fr;
    }
}

.dcc-chart-container {
    position: relative;
    height: 240px;
    padding: 0 var(--space-md) var(--space-md);
}

.dcc-table-scroll {
    overflow-x: auto;
}

.dcc-table {
    width: 100%;
    border-collapse: collapse;
    font-size: .85rem;
}

.dcc-table th {
    text-align: right;
    font-size: .7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .05em;
    color: var(--text-muted);
    padding: var(--space-sm);
    border-bottom: 1px solid var(--border);
}

.dcc-table th:first-child,
.dcc-table td:first-child {
    text-align: left;
}

.dcc-table td {
    padding: var(--space-sm);
    border-bottom: 1px solid var(--border);
    font-family: var(--font-mono);
}

.dcc-table td.val {
    text-align: right;
}

.dcc-step-container {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.dcc-step {
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    overflow: hidden;
}

.dcc-step__header {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-md);
    background: var(--bg-hover);
    border-bottom: 1px solid var(--border);
}

.dcc-step__num {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 22px;
    height: 22px;
    border-radius: 50%;
    background: var(--brand-accent);
    color: #fff;
    font-size: .75rem;
    font-weight: 700;
    flex-shrink: 0;
}

.dcc-step__title {
    font-size: .85rem;
    font-weight: 700;
    color: var(--text-primary);
    margin: 0;
}

.dcc-step__body {
    padding: var(--space-md);
}

.dcc-step__formula {
    font-family: var(--font-mono);
    font-size: .85rem;
    color: var(--text-secondary);
    margin-bottom: var(--space-xs);
}

.dcc-step__result {
    font-family: var(--font-mono);
    font-size: .9rem;
    font-weight: 700;
    color: var(--brand-accent);
}

/* ════════════════════════════════════════════════════════════════
   FUEL CONSTRUCTION (Combustion) — namespace "comb-"
   Estilos propios de simulators/fuel-construction/.
   Este simulador fue construido originalmente contra un sistema de
   tokens distinto (--color-*, --space-N, --font-size-*). El bloque
   .sim-fuel-construction de abajo mapea esos nombres a los tokens
   reales de base.css para que las reglas funcionen sin reescribir
   cada declaración. Se aplica solo dentro de esta página.
   ════════════════════════════════════════════════════════════════ */
.sim-fuel-construction {
    --color-bg: var(--bg-page);
    --color-surface: var(--bg-card);
    --color-surface-alt: var(--bg-hover);
    --color-surface-rgb: 255, 255, 255;
    --color-border: var(--border);
    --color-text: var(--text-primary);
    --color-text-muted: var(--text-secondary);
    --color-primary: var(--brand-accent);
    --color-primary-light: #60a5fa;
    --color-primary-dark: var(--brand-accent-h);
    --color-info: #0ea5e9;
    --font-family: var(--font-sans);
    --font-size-xs: .75rem;
    --font-size-sm: .875rem;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
    --line-height-relaxed: 1.7;
    --space-1: 4px;
    --space-2: 8px;
    --space-3: 12px;
    --space-4: 16px;
    --space-5: 20px;
    --space-6: 24px;
    --space-8: 32px;
    --space-12: 48px;
}

body.dark .sim-fuel-construction {
    --color-surface-rgb: 30, 41, 59;
}

/* ══════════════════════════════════════════════════════
           COMBUSTIÓN — Estilos propios del simulador FASE 1
           Prefijo: comb-  (collision-safe)
           ══════════════════════════════════════════════════════ */

/* ── Engineering Lab Theme (Blueprint) ── */
body.theme-lab {
    --color-bg: var(--bg-page);
    --color-surface: var(--bg-card);
    --color-surface-alt: var(--bg-hover);
    --color-border: var(--border-strong);
    --color-text: var(--text-primary);
    --color-text-muted: var(--text-secondary);
    --color-primary: var(--brand-accent);
    --color-primary-light: var(--brand-accent);
    --color-primary-dark: var(--brand-accent-h);
    background-color: var(--color-bg);
    color: var(--color-text);
}

body.theme-lab .sim-card {
    border-color: var(--color-primary-dark);
    box-shadow: 0 4px 20px rgba(2, 132, 199, 0.1);
}

body.theme-lab .ui-separator span {
    background: var(--color-primary-dark);
    color: white;
}

/* Map global body.dark to SVG icons to match Gold Standard behavior */
body.dark .icon-sun {
    display: block;
}

body.dark .icon-moon {
    display: none;
}

.comb-symbol {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 22px;
    height: 22px;
    border-radius: 4px;
    background: color-mix(in srgb, var(--comp-color) 15%, transparent);
    border: 1px solid color-mix(in srgb, var(--comp-color) 35%, transparent);
    color: var(--comp-color);
    font-size: 11px;
    font-weight: 700;
    font-family: var(--font-mono);
    margin-right: 6px;
    flex-shrink: 0;
}

.comb-value-display {
    font-family: var(--font-mono);
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-semibold);
    color: var(--color-text);
    min-width: 54px;
    text-align: right;
}

.comb-comp-field {
    margin-bottom: var(--space-4);
}

/* ── Composition & humidity sliders — custom track/thumb
   accent-color alone cannot control the unfilled-track background
   consistently across browsers/OS themes. We use full custom
   appearance so every slider shows:
     • unfilled track  → var(--border-strong)  (same light gray as platform)
     • filled thumb    → var(--slider-color)    (per-element accent set inline)
   ── */
.comb-comp-field input[type="range"],
.comb-slider--humidity {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    display: block;
    margin-top: var(--space-2);
    height: 6px;
    border-radius: 3px;
    background: var(--border-strong);
    outline: none;
    cursor: pointer;
}

/* Webkit thumb */
.comb-comp-field input[type="range"]::-webkit-slider-thumb,
.comb-slider--humidity::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--slider-color, var(--brand-accent));
    cursor: pointer;
    transition: transform .1s;
}

.comb-comp-field input[type="range"]::-webkit-slider-thumb:hover,
.comb-slider--humidity::-webkit-slider-thumb:hover {
    transform: scale(1.15);
}

/* Firefox thumb */
.comb-comp-field input[type="range"]::-moz-range-thumb,
.comb-slider--humidity::-moz-range-thumb {
    width: 16px;
    height: 16px;
    border: none;
    border-radius: 50%;
    background: var(--slider-color, var(--brand-accent));
    cursor: pointer;
}

/* Firefox: unfilled track (the part after the thumb) */
.comb-comp-field input[type="range"]::-moz-range-track,
.comb-slider--humidity::-moz-range-track {
    background: var(--border-strong);
    height: 6px;
    border-radius: 3px;
}

/* Humidity slider sets its own --slider-color inline */
.comb-slider--humidity {
    --slider-color: #0ea5e9;
}

.comb-field-note {
    font-size: var(--font-size-xs);
    color: var(--color-text-muted);
    margin-top: var(--space-2);
    font-style: italic;
    line-height: 1.4;
}

.comb-sum-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-2) var(--space-3);
    background: var(--color-surface-alt);
    border-radius: var(--radius-sm);
    margin-bottom: var(--space-4);
    font-size: var(--font-size-xs);
}

.comb-sum-label {
    font-weight: var(--font-weight-semibold);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--color-text-muted);
}

.comb-sum-value {
    font-family: var(--font-mono);
    font-weight: var(--font-weight-bold);
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
}

.comb-sum-value--ok {
    color: var(--color-success);
}

.comb-sum-value--error {
    color: var(--color-danger);
}

.comb-basis-banner {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: var(--space-3) var(--space-4);
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    margin-bottom: var(--space-1);
}

.comb-basis-banner--dry {
    background: color-mix(in srgb, var(--color-success) 8%, transparent);
    border: 1px solid color-mix(in srgb, var(--color-success) 25%, transparent);
    color: var(--color-success);
}

.comb-basis-banner--wet {
    background: color-mix(in srgb, #0ea5e9 8%, transparent);
    border: 1px solid color-mix(in srgb, #0ea5e9 30%, transparent);
    color: #0ea5e9;
}

.comb-composition-table {
    width: 100%;
    border-collapse: collapse;
    font-size: var(--font-size-sm);
}

.comb-composition-table th {
    text-align: left;
    font-size: 10px;
    font-weight: var(--font-weight-semibold);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--color-text-muted);
    padding: var(--space-2) var(--space-3);
    border-bottom: 2px solid var(--color-border);
}

.comb-composition-table td {
    padding: var(--space-2) var(--space-3);
    border-bottom: 1px solid var(--color-border);
    font-family: var(--font-mono);
}

.comb-tbl-element {
    display: flex;
    align-items: center;
    gap: 8px;
    font-family: var(--font-family);
}

.comb-tbl-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
}

.comb-col-dry,
.comb-col-wet {
    text-align: right;
}

.comb-col--inactive {
    color: var(--color-text-muted);
}

.comb-insights {
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
    margin-top: var(--space-3);
}

.comb-insight {
    display: flex;
    gap: var(--space-3);
    padding: var(--space-3) var(--space-4);
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
}

.comb-insight--info {
    background: color-mix(in srgb, var(--color-info) 8%, transparent);
    border-left: 3px solid var(--color-info);
}

.comb-insight--warning {
    background: color-mix(in srgb, var(--color-warning) 8%, transparent);
    border-left: 3px solid var(--color-warning);
}

.comb-insight--danger {
    background: color-mix(in srgb, var(--color-danger) 8%, transparent);
    border-left: 3px solid var(--color-danger);
}

.comb-insight--success {
    background: color-mix(in srgb, var(--color-success) 8%, transparent);
    border-left: 3px solid var(--color-success);
}

.comb-insight--locked {
    background: var(--color-surface-alt);
    border-left: 3px solid var(--color-primary);
    opacity: 0.8;
}

.comb-insight__icon {
    font-size: 1rem;
    flex-shrink: 0;
    line-height: 1.4;
}

.comb-insight__title {
    font-weight: var(--font-weight-semibold);
    color: var(--color-text);
    margin-bottom: 2px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.comb-insight__body {
    color: var(--color-text-muted);
    line-height: var(--line-height-relaxed);
    font-size: var(--font-size-sm);
}

/* Tiered Content Styling */
.pro-tag-inline {
    font-size: 9px;
    font-weight: 800;
    background: var(--color-primary);
    color: white;
    padding: 1px 4px;
    border-radius: 3px;
    margin-left: 8px;
}

.pro-upgrade-link {
    background: none;
    border: none;
    color: var(--color-primary);
    font-size: var(--font-size-xs);
    font-weight: 700;
    text-decoration: underline;
    cursor: pointer;
    padding: 0;
    margin-top: 8px;
}

/* Read More Functionality */
.insight-text-full {
    display: none;
}

.insight-body-wrapper.expanded .insight-text-short {
    display: none;
}

.insight-body-wrapper.expanded .insight-text-full {
    display: block;
}

.insight-body-wrapper.expanded .insight-read-more {
    display: none;
}

.insight-read-more {
    background: none;
    border: none;
    color: var(--color-primary-light);
    font-size: var(--font-size-xs);
    font-weight: 600;
    cursor: pointer;
    padding: 0;
    margin-left: 4px;
    text-decoration: underline;
}

.comb-reset-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 6px 14px;
    background: transparent;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    color: var(--color-text-muted);
    font-size: var(--font-size-xs);
    cursor: pointer;
}

.comb-phase-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 3px 10px;
    border-radius: 999px;
    font-size: 10px;
    font-weight: var(--font-weight-semibold);
    background: color-mix(in srgb, var(--color-primary-light) 12%, transparent);
    border: 1px solid color-mix(in srgb, var(--color-primary-light) 30%, transparent);
    color: var(--color-primary-light);
    margin-bottom: var(--space-2);
}

.resultado-principal {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 16px;
    padding: var(--space-5) var(--space-6);
    box-shadow: var(--shadow-sm);
    position: relative;
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
    min-height: 120px;
    justify-content: center;
}

.resultado-principal::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: linear-gradient(to bottom, #f97316, #ef4444);
    border-top-left-radius: 16px;
    border-bottom-left-radius: 16px;
}

.resultado-principal__title {
    font-size: var(--font-size-xs);
    font-weight: var(--font-weight-bold);
    text-transform: uppercase;
    color: var(--color-text-muted);
    display: flex;
    align-items: center;
    gap: 8px;
}

.resultado-principal__values {
    display: flex;
    align-items: baseline;
    gap: var(--space-8);
    flex-wrap: wrap;
}

.resultado-principal__value--pcs {
    font-size: 36px;
    font-weight: 800;
    font-family: var(--font-mono);
}

.resultado-principal__value--pci {
    font-size: 24px;
    font-weight: 800;
    color: var(--color-text-muted);
    font-family: var(--font-mono);
}

.resultado-principal__unit {
    font-size: var(--font-size-sm);
    margin-left: 4px;
    color: var(--color-text-muted);
}

.resultado-principal__diff {
    font-size: var(--font-size-xs);
    color: var(--color-text-muted);
    opacity: 0.8;
    font-style: italic;
    border-top: 1px solid var(--color-border);
    padding-top: var(--space-2);
}

.resultado-principal__message {
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
    font-style: italic;
    text-align: center;
}

/* ── Reorganización del Layout (Single Column Flow) ── */
.sim-body {
    display: flex;
    flex-direction: column;
    gap: var(--space-6);
    max-width: 1200px;
    margin: 0 auto;
}

.sim-main {
    display: flex;
    flex-direction: column;
    gap: var(--space-6);
    width: 100%;
}

.sim-chart-wrapper {
    aspect-ratio: 16 / 8;
}

@media (max-width: 1024px) {
    .sim-body {
        padding: 0 var(--space-4);
    }
}

/* ── Collapsible Section ── */
.collapsible {
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    background: var(--color-surface);
    overflow: hidden;
    transition: all 0.3s ease;
}

.collapsible-header {
    padding: var(--space-4) var(--space-5);
    background: var(--color-surface-alt);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: space-between;
    user-select: none;
    transition: background 0.2s ease;
}

.collapsible-header:hover {
    background: color-mix(in srgb, var(--color-surface-alt) 95%, black);
}

body.dark .collapsible-header:hover {
    background: color-mix(in srgb, var(--color-surface-alt) 90%, white);
}

.collapsible-header h2 {
    margin-bottom: 0;
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
    display: flex;
    align-items: center;
    gap: 10px;
}

.collapsible-icon {
    display: inline-block;
    transition: transform 0.3s ease;
    font-size: 10px;
    color: var(--color-text-muted);
}

.collapsible.open .collapsible-icon {
    transform: rotate(90deg);
}

.collapsible-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out, opacity 0.3s ease;
    opacity: 0;
}

.collapsible.open .collapsible-content {
    max-height: 1200px;
    /* Suficiente para la tabla */
    opacity: 1;
    border-top: 1px solid var(--color-border);
}

.collapsible-inner {
    padding: var(--space-5);
}

/* ── PRO Tiering System ── */
.pro-locked-container {
    position: relative;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    background: var(--color-surface);
    overflow: hidden;
    transition: all 0.3s ease;
}

.pro-locked-content {
    filter: blur(8px);
    pointer-events: none;
    user-select: none;
    opacity: 0.5;
    padding: var(--space-6);
    /* Simular contenido PRO */
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.pro-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: rgba(var(--color-surface-rgb, 255, 255, 255), 0.2);
    backdrop-filter: blur(1px);
    z-index: 10;
    text-align: center;
    padding: var(--space-6);
}

.pro-badge-mini {
    display: inline-flex;
    align-items: center;
    padding: 2px 8px;
    background: var(--color-primary);
    color: white;
    border-radius: 4px;
    font-size: 10px;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--space-2);
}

.pro-lock-icon {
    font-size: 1.8rem;
    margin-bottom: var(--space-2);
}

.pro-lock-title {
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: 0.5rem;
}

.pro-lock-text {
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
    margin-bottom: 1.5rem;
    max-width: 320px;
    line-height: 1.4;
}

.pro-upgrade-btn {
    padding: 10px 24px;
    background: var(--color-primary);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    font-weight: var(--font-weight-bold);
    font-size: var(--font-size-sm);
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.3);
}

.pro-upgrade-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(99, 102, 241, 0.4);
}

/* ── PRO Teasers (Compact) ── */
.pro-teaser-card {
    display: flex;
    align-items: center;
    gap: var(--space-4);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-4) var(--space-5);
    margin-bottom: var(--space-4);
    cursor: pointer;
    transition: all 0.2s ease;
}

.pro-teaser-card:hover {
    border-color: var(--color-primary-light);
    background: var(--color-surface-alt);
}

.pro-teaser-icon {
    font-size: 1.5rem;
    background: color-mix(in srgb, var(--color-primary) 10%, transparent);
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 12px;
}

.pro-teaser-body {
    flex: 1;
}

.pro-teaser-title {
    font-weight: 700;
    font-size: var(--font-size-sm);
    margin-bottom: 2px;
}

.pro-teaser-desc {
    font-size: var(--font-size-xs);
    color: var(--color-text-muted);
}

.pro-teaser-cta {
    font-size: var(--font-size-xs);
    font-weight: 700;
    color: var(--color-primary);
    display: flex;
    align-items: center;
    gap: 4px;
}

/* ── Separators ── */
.ui-separator {
    display: flex;
    align-items: center;
    gap: var(--space-4);
    margin: var(--space-8) 0 var(--space-4);
}

.ui-separator::before,
.ui-separator::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--color-border);
}

.ui-separator span {
    font-size: 10px;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-text-muted);
    background: var(--color-surface-alt);
    padding: 2px 10px;
    border-radius: 999px;
}

/* ── Tiered Modal Styling ── */
.sim-modal__content--tiered {
    max-width: 500px;
    text-align: center;
}

.sim-modal__features {
    text-align: left;
    margin: var(--space-4) auto;
    max-width: 340px;
    font-size: var(--font-size-sm);
}

.sim-modal__pricing-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 10px;
    margin: var(--space-6) 0;
}

.sim-modal__price-card {
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--space-3) var(--space-4);
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--color-surface-alt);
    cursor: pointer;
    transition: all 0.2s ease;
}

.sim-modal__price-card:hover {
    border-color: var(--color-primary);
    transform: scale(1.02);
}

.sim-modal__price-label {
    font-size: var(--font-size-xs);
    font-weight: 700;
    color: var(--color-text);
}

.sim-modal__price-value {
    font-family: var(--font-mono);
    font-weight: 800;
    color: var(--color-primary);
}

.sim-modal__price-note {
    font-size: 9px;
    color: var(--color-text-muted);
    position: absolute;
    bottom: -14px;
    left: 10px;
    display: none;
}

/* ── Page-level container spacing ───────────────────────
           sim-layout__main / sim-container are used in place of
           .sim-shell here. Apply equivalent outer padding so the
           header content has the same breathing room as the cards. */
.sim-layout__main {
    padding-top: var(--space-8);
}

.sim-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-6) var(--space-12);
}

@media (max-width: 1024px) {
    .sim-layout__main {
        padding-top: var(--space-6);
    }

    .sim-container {
        padding: 0 var(--space-4) var(--space-8);
    }
}

/* ── Auditoría 2026-09-15: clases usadas en fuel-construction que no
   tenían regla CSS en ningún lado (bloqueante #1 del informe) ──
   NOTA (2026-09-17): el bloque "Page header" original (.sim-header,
   .sim-badge, etc.) se eliminó — el HTML pasó a usar el .sim-hero
   real del sitio (full-width, con breadcrumb), que ya tenía sus
   propios estilos desde el template base. */

/* Card header/title (Parameter Adjustment) */
.sim-card__header {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.sim-card__title {
    font-size: 1.05rem;
    font-weight: var(--font-weight-bold);
    color: var(--color-text);
}

/* Chart card */
.sim-chart-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-6);
}

.sim-chart-card__header {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: var(--space-2);
}

.sim-chart-card__title {
    font-size: 1rem;
    font-weight: var(--font-weight-bold);
    color: var(--color-text);
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.sim-chart-card__subtitle {
    font-size: var(--font-size-xs);
    color: var(--color-text-muted);
}

/* System-model note */
.simulator-note {
    background: color-mix(in srgb, var(--color-info) 6%, transparent);
    border: 1px solid color-mix(in srgb, var(--color-info) 25%, transparent);
    border-radius: var(--radius-md);
    padding: var(--space-4);
}

.simulator-note__header {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    font-weight: var(--font-weight-semibold);
    color: var(--color-info);
    margin-bottom: var(--space-2);
    font-size: var(--font-size-sm);
}

.simulator-note__icon {
    font-size: 1rem;
}

.simulator-note__body {
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
    line-height: var(--line-height-relaxed);
}

/* Auto-Tutor card (Learning Mode — código inactivo, pero si se
   reactiva algún día ya tiene estilos listos) */
.tutor-card {
    background: color-mix(in srgb, var(--color-primary) 6%, transparent);
    border: 1px solid color-mix(in srgb, var(--color-primary) 25%, transparent);
    border-left: 3px solid var(--color-primary);
    border-radius: var(--radius-md);
    padding: var(--space-4);
    margin-top: var(--space-4);
}

.tutor-card__header {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    font-weight: var(--font-weight-bold);
    color: var(--color-primary);
    margin-bottom: var(--space-2);
    font-size: var(--font-size-sm);
}

.tutor-card__body {
    font-size: var(--font-size-sm);
    color: var(--color-text);
    line-height: var(--line-height-relaxed);
}

.tutor-card__footer {
    margin-top: var(--space-2);
    padding-top: var(--space-2);
    border-top: 1px solid var(--color-border);
    font-size: var(--font-size-xs);
    color: var(--color-text-muted);
    font-style: italic;
}

/* Composition table — water & total rows */
.comb-row-water {
    background: color-mix(in srgb, var(--color-info) 5%, transparent);
}

.comb-row-total {
    font-weight: var(--font-weight-bold);
    border-top: 2px solid var(--color-border);
}

.comb-row-total td {
    color: var(--color-text);
}

/* Educational section headings (este simulador usa BEM en vez de h2/h3 sueltos) */
.edu-section__heading {
    font-size: 1.25rem;
    font-weight: var(--font-weight-bold);
    color: var(--color-text);
    margin-bottom: var(--space-4);
    padding-bottom: var(--space-2);
    border-bottom: 2px solid var(--color-primary);
    display: inline-block;
}

.edu-section__subheading {
    font-size: 1rem;
    font-weight: var(--font-weight-bold);
    color: var(--color-text);
    margin: var(--space-4) 0 var(--space-2);
}

.edu-steps {
    padding-left: var(--space-6);
    color: var(--color-text-muted);
    margin-bottom: var(--space-4);
    list-style: decimal;
}

.edu-steps li {
    margin-bottom: var(--space-2);
    line-height: var(--line-height-relaxed);
}

/* FAQ — versión BEM (div planos en vez de <details>/<summary>) */
.sim-fuel-construction .edu-faq-item+.edu-faq-item {
    margin-top: var(--space-4);
}

.edu-faq-item__question {
    font-weight: var(--font-weight-bold);
    color: var(--color-text);
    padding: var(--space-4) var(--space-4) 0;
    margin-bottom: var(--space-2);
    font-size: var(--font-size-sm);
}

.edu-faq-item__answer {
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
    line-height: var(--line-height-relaxed);
    padding: 0 var(--space-4) var(--space-4);
    margin: 0;
}

/* Info tooltip (ⓘ) */
.info-tooltip {
    position: relative;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--color-surface-alt);
    color: var(--color-text-muted);
    font-size: 11px;
    cursor: help;
}

.info-tooltip::after {
    content: attr(data-tooltip);
    position: absolute;
    bottom: 125%;
    left: 50%;
    transform: translateX(-50%);
    width: 220px;
    background: var(--color-text);
    color: var(--color-surface);
    font-size: var(--font-size-xs);
    font-weight: 400;
    line-height: 1.4;
    padding: var(--space-2) var(--space-3);
    border-radius: var(--radius-sm);
    opacity: 0;
    pointer-events: none;
    transition: opacity .15s ease;
    z-index: 20;
    text-transform: none;
    letter-spacing: normal;
}

.info-tooltip:hover::after,
.info-tooltip:focus::after {
    opacity: 1;
}

/* ════════════════════════════════════════════════════════════════
   COMBUSTION CHIMNEY ANALYSER — namespace "co-"
   Component-specific styles for the Combustion Chimney Analyser
   simulator. Does not use the generic .sim-* system beyond
   composition; kept isolated under its own "co-" prefix so it
   can't collide with other simulators.
   ════════════════════════════════════════════════════════════════ */

/* ── Layout shell: two-column on wide screens, single on mobile ── */
.co-shell {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-lg);
    align-items: start;
}

@media (max-width: 860px) {
    .co-shell {
        grid-template-columns: 1fr;
    }
}

/* ── Panel card — shared container ── */
.co-panel {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
}

/* ── Panel header ── */
.co-panel__header {
    display: flex;
    align-items: center;
    gap: .75rem;
    margin-bottom: var(--space-lg);
    padding-bottom: var(--space-md);
    border-bottom: 1px solid var(--border);
}

.co-panel__icon {
    width: 2rem;
    height: 2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(37, 99, 235, .1);
    color: var(--brand-accent);
    border-radius: var(--radius-md);
    flex-shrink: 0;
}

.co-panel__title {
    font-size: .875rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
    text-transform: uppercase;
    letter-spacing: .04em;
}

.co-panel__subtitle {
    font-size: .75rem;
    color: var(--text-muted);
    margin-left: auto;
}

/* ── Custom fuel panel (was inline styles — moved here per audit) ── */
.co-custom-panel {
    display: none;
    flex-direction: column;
    gap: var(--space-md);
    padding: var(--space-md);
    background: var(--bg-hover);
    border: 1px dashed var(--border-strong);
    border-radius: var(--radius-md);
}

.co-custom-panel__title {
    font-size: .7rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: .04em;
    margin-bottom: .25rem;
}

/* ── Form fields grid ── */
.co-fields {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.co-field {
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
}

.co-field__label {
    font-size: .75rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: .05em;
}

.co-field__label span {
    /* unit inside label */
    font-weight: 400;
    text-transform: none;
    color: var(--text-muted);
    font-family: var(--font-mono);
}

.co-field__input,
.co-field__select {
    width: 100%;
    padding: .625rem .875rem;
    font-size: .875rem;
    font-family: inherit;
    color: var(--text-primary);
    background: var(--bg-hover);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    transition: border-color .15s, box-shadow .15s;
    outline: none;
    -webkit-appearance: none;
    appearance: none;
    box-sizing: border-box;
}

.co-field__select {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right .875rem center;
    padding-right: 2.5rem;
    cursor: pointer;
}

.co-field__input:focus,
.co-field__select:focus {
    border-color: var(--brand-accent);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, .12);
}

.co-field__input:hover,
.co-field__select:hover {
    border-color: var(--brand-accent);
}

/* CO2max indicator under CO2 input */
.co-field__note {
    font-size: .7rem;
    color: var(--text-muted);
    font-family: var(--font-mono);
    padding: .25rem .5rem;
    background: var(--border);
    border-radius: var(--radius-sm);
    display: inline-block;
    width: fit-content;
}

/* ── Error message area ── */
.co-error-box {
    display: none;
    padding: .75rem 1rem;
    background: rgba(220, 38, 38, .08);
    border: 1px solid rgba(220, 38, 38, .25);
    border-left: 3px solid var(--color-danger);
    border-radius: var(--radius-md);
    font-size: .875rem;
    color: var(--color-danger);
    margin-top: var(--space-md);
}

.co-error-box.is-visible {
    display: block;
}

/* ── Action buttons ── */
.co-btn-calculate {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    width: 100%;
    padding: .75rem 1.5rem;
    font-size: .875rem;
    font-weight: 600;
    font-family: inherit;
    color: #fff;
    background: var(--brand-accent);
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    letter-spacing: .02em;
    transition: background .15s, transform .1s, box-shadow .15s;
    margin-top: var(--space-lg);
}

.co-btn-calculate:hover {
    background: var(--brand-accent-h);
    box-shadow: 0 4px 12px rgba(37, 99, 235, .25);
}

.co-btn-calculate:active {
    transform: scale(.98);
}

.co-btn-reset {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    padding: .625rem 1rem;
    font-size: .75rem;
    font-weight: 600;
    font-family: inherit;
    color: var(--text-secondary);
    background: transparent;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    cursor: pointer;
    letter-spacing: .03em;
    transition: background .15s, border-color .15s;
    margin-top: var(--space-sm);
}

.co-btn-reset:hover {
    background: var(--border);
}

/* ── Results panel — spans full width ── */
.co-results-wrapper {
    grid-column: 1 / -1;
    display: none;
    /* hidden until calculation */
}

.co-results-wrapper.is-visible {
    display: block;
}

/* ── Diagnostic badge ── */
.co-diagnostic {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: .875rem 1.25rem;
    border-radius: var(--radius-md);
    border: 1px solid transparent;
    margin-bottom: var(--space-lg);
    font-size: .875rem;
    font-weight: 500;
    transition: background .25s, color .25s;
}

.co-diagnostic__dot {
    width: .625rem;
    height: .625rem;
    border-radius: 50%;
    flex-shrink: 0;
}

/* State: optimal (exceso < 15%) */
.co-diagnostic--optimal {
    background: #f0fdf4;
    border-color: #bbf7d0;
    color: #15803d;
}

.co-diagnostic--optimal .co-diagnostic__dot {
    background: #22c55e;
}

/* State: acceptable (15% <= exceso <= 50%) */
.co-diagnostic--acceptable {
    background: #eff6ff;
    border-color: #bfdbfe;
    color: #1d4ed8;
}

.co-diagnostic--acceptable .co-diagnostic__dot {
    background: #3b82f6;
}

/* State: high (exceso > 50%) */
.co-diagnostic--high {
    background: #fff7ed;
    border-color: #fed7aa;
    color: #c2410c;
}

.co-diagnostic--high .co-diagnostic__dot {
    background: #f97316;
}

/* ── Results grid: 5 metric cards ── */
.co-metrics {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: var(--space-md);
}

.co-metric {
    display: flex;
    flex-direction: column;
    gap: .375rem;
    padding: 1rem 1.125rem;
    background: var(--bg-hover);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    transition: border-color .15s;
}

/* Highlight card — key outputs */
.co-metric--highlight {
    border-color: var(--brand-accent);
    background: rgba(37, 99, 235, .06);
}

.co-metric--highlight .co-metric__label {
    color: var(--brand-accent);
}

.co-metric__label {
    font-size: .7rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: .05em;
}

.co-metric__value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    font-family: var(--font-mono);
    line-height: 1;
}

.co-metric__unit {
    font-size: .7rem;
    color: var(--text-muted);
    font-family: var(--font-mono);
}

/* ── Formula reference note ── */
.co-formula-note {
    margin-top: var(--space-lg);
    padding: .875rem 1rem;
    background: var(--border);
    border-radius: var(--radius-md);
    font-size: .7rem;
    color: var(--text-secondary);
    font-family: var(--font-mono);
    line-height: 1.7;
}

.co-formula-note strong {
    font-weight: 600;
    color: var(--text-primary);
}

/* ── Dark-mode safety overrides (inherits --* vars from base.css) ── */
body.dark .co-error-box {
    background: #450a0a;
    border-color: #7f1d1d;
    color: #fca5a5;
}

body.dark .co-diagnostic--optimal {
    background: #052e16;
    border-color: #14532d;
    color: #86efac;
}

body.dark .co-diagnostic--acceptable {
    background: #172554;
    border-color: #1e40af;
    color: #93c5fd;
}

body.dark .co-diagnostic--high {
    background: #431407;
    border-color: #9a3412;
    color: #fdba74;
}

/* ════════════════════════════════════════════════════════════════
   PIPE HEAD LOSS — namespace "phl-"
   Component-specific styles for the Pipe Head Loss simulator.
   Composes on top of the generic .sim-* system; kept isolated
   under its own "phl-" prefix so it can't collide with other
   simulators.
   ════════════════════════════════════════════════════════════════ */

.phl-slider-row {
    display: grid;
    grid-template-columns: 1fr 90px;
    gap: var(--space-sm);
    align-items: center;
}

.phl-slider-row--unit {
    grid-template-columns: 1fr 80px 60px;
}

@media (max-width: 480px) {
    .phl-slider-row--unit {
        grid-template-columns: 1fr;
    }
}

.phl-slider {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 6px;
    border-radius: 3px;
    background: var(--border-strong);
    outline: none;
    cursor: pointer;
}

.phl-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--brand-accent);
    cursor: pointer;
    transition: transform .1s;
}

.phl-slider::-webkit-slider-thumb:hover {
    transform: scale(1.1);
}

.phl-slider::-moz-range-thumb {
    width: 16px;
    height: 16px;
    border: none;
    border-radius: 50%;
    background: var(--brand-accent);
    cursor: pointer;
}

.phl-unit-select {
    padding: 9px 28px 9px 10px;
    font-size: .8rem;
}

.phl-precision {
    font-size: .73rem;
    color: var(--text-muted);
    margin-top: var(--space-xs);
    font-family: var(--font-mono);
}

.phl-precision span {
    color: var(--text-secondary);
    font-weight: 600;
}

/* ── Decision Engine — velocity gauge ─────────────────────────── */
.phl-gauge {
    margin-top: var(--space-md);
    padding-top: var(--space-md);
    border-top: 1px dashed var(--border);
}

.phl-gauge-header {
    display: flex;
    justify-content: space-between;
    font-size: .75rem;
    color: var(--text-muted);
    margin-bottom: var(--space-xs);
}

.phl-gauge-header strong {
    color: var(--text-primary);
    font-family: var(--font-mono);
}

.phl-gauge-track {
    position: relative;
    height: 8px;
    background: var(--bg-hover);
    border: 1px solid var(--border);
    border-radius: 4px;
    overflow: hidden;
}

.phl-gauge-zone {
    position: absolute;
    top: 0;
    height: 100%;
}

.phl-gauge-zone--low {
    left: 0;
    background: var(--color-warning);
    opacity: .3;
}

.phl-gauge-zone--mid {
    background: var(--color-success);
    opacity: .3;
}

.phl-gauge-zone--high {
    background: var(--color-danger);
    opacity: .3;
}

.phl-gauge-marker {
    position: absolute;
    top: 0;
    width: 3px;
    height: 100%;
    background: var(--brand-accent);
    transform: translateX(-50%);
    border-radius: 2px;
}

.phl-gauge-scale {
    display: flex;
    justify-content: space-between;
    position: relative;
    font-size: .68rem;
    color: var(--text-muted);
    margin-top: 4px;
}

/* Larger charts for this simulator's two Chart.js canvases */
.phl-chart-tall {
    min-height: 380px;
}

#lossChart,
#optimChart {
    max-height: 380px;
}

@media (max-width: 640px) {
    .phl-chart-tall {
        min-height: 280px;
    }

    #lossChart,
    #optimChart {
        max-height: 280px;
    }
}

/* ════════════════════════════════════════════════════════════════
   ENTROPY T-S DIAGRAM (GAS) — namespace "ent-"
   Component-specific styles for the Entropy T-s Diagram simulator.
   Everything else reuses the shared .sim-* system (sim-panel,
   sim-field, sim-input-wrap, sim-advanced, sim-results-grid,
   sim-result-card, status-banner, sim-chart-wrap, is-hidden,
   edu-grid, edu-faq-item) — only the slider needs its own styling.
   ════════════════════════════════════════════════════════════════ */

.ent-slider-row {
    display: flex;
    align-items: center;
    margin-top: var(--space-xs);
}

.ent-slider {
    flex: 1;
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 6px;
    border-radius: 3px;
    background: var(--border-strong);
    outline: none;
    cursor: pointer;
}

.ent-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--brand-accent);
    cursor: pointer;
    transition: transform .1s;
}

.ent-slider::-webkit-slider-thumb:hover {
    transform: scale(1.1);
}

.ent-slider::-moz-range-thumb {
    width: 16px;
    height: 16px;
    border: none;
    border-radius: 50%;
    background: var(--brand-accent);
    cursor: pointer;
}

/* =========================================================
   Power Converter — namespaced "pwc-" block
   Append to the end of assets/css/simulator.css
   ========================================================= */

.pwc-table-wrap {
    overflow-x: auto;
}

.pwc-table {
    min-width: 420px;
}

.pwc-value-cell {
    font-family: var(--font-mono, 'JetBrains Mono', monospace);
    text-align: right;
    white-space: nowrap;
}

.pwc-row--active {
    background: var(--bg-hover);
}

.pwc-row--active td {
    font-weight: 600;
    color: var(--brand-accent);
}

.pwc-empty-state {
    color: var(--text-secondary);
    padding: var(--space-lg, 1.5rem) 0;
    text-align: center;
}

@media (max-width: 640px) {
    .pwc-table {
        min-width: 320px;
        font-size: 0.875rem;
    }
}

/* ============================================================
   Energy Converter (enc-) — namespaced block
   Append to the end of assets/css/simulator.css
   No custom slider needed (text input + select only).
   ============================================================ */

.enc-table-wrap {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.enc-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9375rem;
}

.enc-table th,
.enc-table td {
    padding: 0.65rem 0.85rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
    white-space: nowrap;
}

.enc-table th {
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.8125rem;
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.enc-table tbody tr:nth-child(even) {
    background: var(--bg-hover);
}

.enc-table tbody tr.enc-row--active {
    background: var(--bg-hover);
    border-left: 3px solid var(--brand-accent);
    font-weight: 600;
}

.enc-value-cell {
    font-family: 'JetBrains Mono', monospace;
    color: var(--text-primary);
}

@media (max-width: 640px) {

    .enc-table th,
    .enc-table td {
        padding: 0.5rem 0.6rem;
        font-size: 0.875rem;
    }
}

/* ============================================================
   Length Converter (lnc-) — namespaced block
   Append to the end of assets/css/simulator.css
   No custom slider needed (text input + select only).
   Mirrors the enc- block from Energy Converter.
   ============================================================ */

.lnc-table-wrap {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.lnc-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9375rem;
}

.lnc-table th,
.lnc-table td {
    padding: 0.65rem 0.85rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
    white-space: nowrap;
}

.lnc-table th {
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.8125rem;
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.lnc-table tbody tr:nth-child(even) {
    background: var(--bg-hover);
}

.lnc-table tbody tr.lnc-row--active {
    background: var(--bg-hover);
    border-left: 3px solid var(--brand-accent);
    font-weight: 600;
}

.lnc-value-cell {
    font-family: 'JetBrains Mono', monospace;
    color: var(--text-primary);
}

@media (max-width: 640px) {

    .lnc-table th,
    .lnc-table td {
        padding: 0.5rem 0.6rem;
        font-size: 0.875rem;
    }
}

/* ============================================================
   Mass / Weight Converter (msc-) — namespaced block
   Append to the end of assets/css/simulator.css
   No custom slider needed (text input + select only).
   Mirrors the enc-/lnc- blocks from Energy/Length Converter.
   ============================================================ */

.msc-table-wrap {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.msc-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9375rem;
}

.msc-table th,
.msc-table td {
    padding: 0.65rem 0.85rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
    white-space: nowrap;
}

.msc-table th {
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.8125rem;
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.msc-table tbody tr:nth-child(even) {
    background: var(--bg-hover);
}

.msc-table tbody tr.msc-row--active {
    background: var(--bg-hover);
    border-left: 3px solid var(--brand-accent);
    font-weight: 600;
}

.msc-value-cell {
    font-family: 'JetBrains Mono', monospace;
    color: var(--text-primary);
}

@media (max-width: 640px) {

    .msc-table th,
    .msc-table td {
        padding: 0.5rem 0.6rem;
        font-size: 0.875rem;
    }
}

/* ============================================================
   Temperature Converter (tpc-) — namespaced block
   Append to the end of assets/css/simulator.css
   No custom slider needed (text input + select only).
   Mirrors the enc-/lnc-/msc- blocks from the other unit converters.
   ============================================================ */

.tpc-table-wrap {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.tpc-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9375rem;
}

.tpc-table th,
.tpc-table td {
    padding: 0.65rem 0.85rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
    white-space: nowrap;
}

.tpc-table th {
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.8125rem;
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.tpc-table tbody tr:nth-child(even) {
    background: var(--bg-hover);
}

.tpc-table tbody tr.tpc-row--active {
    background: var(--bg-hover);
    border-left: 3px solid var(--brand-accent);
    font-weight: 600;
}

.tpc-value-cell {
    font-family: 'JetBrains Mono', monospace;
    color: var(--text-primary);
}

@media (max-width: 640px) {

    .tpc-table th,
    .tpc-table td {
        padding: 0.5rem 0.6rem;
        font-size: 0.875rem;
    }
}

/* ============================================================
   Volume Converter (vol-) — namespaced block
   Append to the end of assets/css/simulator.css
   No custom slider needed (text input + select only).
   Mirrors the enc-/lnc-/msc-/tpc- blocks from the other unit converters.
   ============================================================ */

.vol-table-wrap {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.vol-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9375rem;
}

.vol-table th,
.vol-table td {
    padding: 0.65rem 0.85rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
    white-space: nowrap;
}

.vol-table th {
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.8125rem;
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.vol-table tbody tr:nth-child(even) {
    background: var(--bg-hover);
}

.vol-table tbody tr.vol-row--active {
    background: var(--bg-hover);
    border-left: 3px solid var(--brand-accent);
    font-weight: 600;
}

.vol-value-cell {
    font-family: 'JetBrains Mono', monospace;
    color: var(--text-primary);
}

@media (max-width: 640px) {

    .vol-table th,
    .vol-table td {
        padding: 0.5rem 0.6rem;
        font-size: 0.875rem;
    }
}

/* ============================================================
   Data Storage Converter (dsc-) — namespaced block
   Append to the end of assets/css/simulator.css
   No custom slider needed (text input + select only).
   Mirrors the enc-/lnc-/msc-/tpc-/vol- blocks from the other unit converters.
   ============================================================ */

.dsc-table-wrap {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.dsc-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9375rem;
}

.dsc-table th,
.dsc-table td {
    padding: 0.65rem 0.85rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
    white-space: nowrap;
}

.dsc-table th {
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.8125rem;
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.dsc-table tbody tr:nth-child(even) {
    background: var(--bg-hover);
}

.dsc-table tbody tr.dsc-row--active {
    background: var(--bg-hover);
    border-left: 3px solid var(--brand-accent);
    font-weight: 600;
}

.dsc-value-cell {
    font-family: 'JetBrains Mono', monospace;
    color: var(--text-primary);
}

@media (max-width: 640px) {

    .dsc-table th,
    .dsc-table td {
        padding: 0.5rem 0.6rem;
        font-size: 0.875rem;
    }
}

/* ============================================================
   Area Converter (are-) — namespaced block
   Append to the end of assets/css/simulator.css
   No custom slider needed (text input + select only).
   Mirrors the enc-/lnc-/msc-/tpc-/vol-/dsc- blocks from the other
   unit converters.
   ============================================================ */

.are-table-wrap {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.are-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9375rem;
}

.are-table th,
.are-table td {
    padding: 0.65rem 0.85rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
    white-space: nowrap;
}

.are-table th {
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.8125rem;
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.are-table tbody tr:nth-child(even) {
    background: var(--bg-hover);
}

.are-table tbody tr.are-row--active {
    background: var(--bg-hover);
    border-left: 3px solid var(--brand-accent);
    font-weight: 600;
}

.are-value-cell {
    font-family: 'JetBrains Mono', monospace;
    color: var(--text-primary);
}

@media (max-width: 640px) {

    .are-table th,
    .are-table td {
        padding: 0.5rem 0.6rem;
        font-size: 0.875rem;
    }
}

/* ============================================================
   Speed Converter (spc-) — namespaced block
   Append to the end of assets/css/simulator.css
   No custom slider needed (text input + select only).
   Mirrors the enc-/lnc-/msc-/tpc-/vol-/dsc-/are- blocks from the
   other unit converters.
   ============================================================ */

.spc-table-wrap {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.spc-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9375rem;
}

.spc-table th,
.spc-table td {
    padding: 0.65rem 0.85rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
    white-space: nowrap;
}

.spc-table th {
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.8125rem;
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.spc-table tbody tr:nth-child(even) {
    background: var(--bg-hover);
}

.spc-table tbody tr.spc-row--active {
    background: var(--bg-hover);
    border-left: 3px solid var(--brand-accent);
    font-weight: 600;
}

.spc-value-cell {
    font-family: 'JetBrains Mono', monospace;
    color: var(--text-primary);
}

@media (max-width: 640px) {

    .spc-table th,
    .spc-table td {
        padding: 0.5rem 0.6rem;
        font-size: 0.875rem;
    }
}

/* ============================================================
   Pressure Converter (prc-) — namespaced block
   Append to the end of assets/css/simulator.css
   No custom slider needed (text input + select only).
   Mirrors the enc-/lnc-/msc-/tpc-/vol-/dsc-/are-/spc- blocks from
   the other unit converters.
   ============================================================ */

.prc-table-wrap {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.prc-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9375rem;
}

.prc-table th,
.prc-table td {
    padding: 0.65rem 0.85rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
    white-space: nowrap;
}

.prc-table th {
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.8125rem;
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.prc-table tbody tr:nth-child(even) {
    background: var(--bg-hover);
}

.prc-table tbody tr.prc-row--active {
    background: var(--bg-hover);
    border-left: 3px solid var(--brand-accent);
    font-weight: 600;
}

.prc-value-cell {
    font-family: 'JetBrains Mono', monospace;
    color: var(--text-primary);
}

@media (max-width: 640px) {

    .prc-table th,
    .prc-table td {
        padding: 0.5rem 0.6rem;
        font-size: 0.875rem;
    }
}

/* ============================================================
   Torque Converter (trq-) — namespaced block
   Append to the end of assets/css/simulator.css
   No custom slider needed (text input + select only).
   Mirrors the enc-/lnc-/msc-/tpc-/vol-/dsc-/are-/spc-/prc-/frc- blocks
   from the other unit converters.
   ============================================================ */

.trq-table-wrap {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.trq-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9375rem;
}

.trq-table th,
.trq-table td {
    padding: 0.65rem 0.85rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
    white-space: nowrap;
}

.trq-table th {
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.8125rem;
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.trq-table tbody tr:nth-child(even) {
    background: var(--bg-hover);
}

.trq-table tbody tr.trq-row--active {
    background: var(--bg-hover);
    border-left: 3px solid var(--brand-accent);
    font-weight: 600;
}

.trq-value-cell {
    font-family: 'JetBrains Mono', monospace;
    color: var(--text-primary);
}

@media (max-width: 640px) {

    .trq-table th,
    .trq-table td {
        padding: 0.5rem 0.6rem;
        font-size: 0.875rem;
    }
}

/* ============================================================
   Mass / Weight Converter (msc-) — namespaced block
   Append to the end of assets/css/simulator.css
   No custom slider needed (text input + select only).
   Mirrors the enc-/lnc- blocks from Energy/Length Converter.
   ============================================================ */

.msc-table-wrap {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.msc-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9375rem;
}

.msc-table th,
.msc-table td {
    padding: 0.65rem 0.85rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
    white-space: nowrap;
}

.msc-table th {
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.8125rem;
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.msc-table tbody tr:nth-child(even) {
    background: var(--bg-hover);
}

.msc-table tbody tr.msc-row--active {
    background: var(--bg-hover);
    border-left: 3px solid var(--brand-accent);
    font-weight: 600;
}

.msc-value-cell {
    font-family: 'JetBrains Mono', monospace;
    color: var(--text-primary);
}

@media (max-width: 640px) {

    .msc-table th,
    .msc-table td {
        padding: 0.5rem 0.6rem;
        font-size: 0.875rem;
    }
}

/* ============================================================
   Fuel Consumption Converter (fcc-) — namespaced block
   Append to the end of assets/css/simulator.css
   No custom slider needed (text input + select only).
   Mirrors the enc-/lnc-/msc-/tpc-/vol-/dsc-/are-/spc-/prc-/frc-/trq-/flr-
   blocks from the other unit converters.
   ============================================================ */

.fcc-table-wrap {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.fcc-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9375rem;
}

.fcc-table th,
.fcc-table td {
    padding: 0.65rem 0.85rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
    white-space: nowrap;
}

.fcc-table th {
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.8125rem;
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.fcc-table tbody tr:nth-child(even) {
    background: var(--bg-hover);
}

.fcc-table tbody tr.fcc-row--active {
    background: var(--bg-hover);
    border-left: 3px solid var(--brand-accent);
    font-weight: 600;
}

.fcc-value-cell {
    font-family: 'JetBrains Mono', monospace;
    color: var(--text-primary);
}

@media (max-width: 640px) {

    .fcc-table th,
    .fcc-table td {
        padding: 0.5rem 0.6rem;
        font-size: 0.875rem;
    }
}

/* ============================================================
   Force Converter (frc-) — namespaced block
   Append to the end of assets/css/simulator.css
   No custom slider needed (text input + select only).
   Mirrors the enc-/lnc-/msc-/tpc-/vol-/dsc-/are-/spc-/prc- blocks
   from the other unit converters.
   ============================================================ */

.frc-table-wrap {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.frc-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9375rem;
}

.frc-table th,
.frc-table td {
    padding: 0.65rem 0.85rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
    white-space: nowrap;
}

.frc-table th {
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.8125rem;
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.frc-table tbody tr:nth-child(even) {
    background: var(--bg-hover);
}

.frc-table tbody tr.frc-row--active {
    background: var(--bg-hover);
    border-left: 3px solid var(--brand-accent);
    font-weight: 600;
}

.frc-value-cell {
    font-family: 'JetBrains Mono', monospace;
    color: var(--text-primary);
}

@media (max-width: 640px) {

    .frc-table th,
    .frc-table td {
        padding: 0.5rem 0.6rem;
        font-size: 0.875rem;
    }
}

/* ============================================================
   Flow Rate Converter (flr-) — namespaced block
   Append to the end of assets/css/simulator.css
   No custom slider needed (text input + select only).
   Mirrors the enc-/lnc-/msc-/tpc-/vol-/dsc-/are-/spc-/prc-/frc-/trq-
   blocks from the other unit converters.
   ============================================================ */

.flr-table-wrap {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.flr-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9375rem;
}

.flr-table th,
.flr-table td {
    padding: 0.65rem 0.85rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
    white-space: nowrap;
}

.flr-table th {
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.8125rem;
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.flr-table tbody tr:nth-child(even) {
    background: var(--bg-hover);
}

.flr-table tbody tr.flr-row--active {
    background: var(--bg-hover);
    border-left: 3px solid var(--brand-accent);
    font-weight: 600;
}

.flr-value-cell {
    font-family: 'JetBrains Mono', monospace;
    color: var(--text-primary);
}

@media (max-width: 640px) {

    .flr-table th,
    .flr-table td {
        padding: 0.5rem 0.6rem;
        font-size: 0.875rem;
    }
}

/* ----------------------------------------------------------------
   GAS COMBUSTION (gc-)
   ---------------------------------------------------------------- */
/* ════════════════════════════════════════════════════════════════
   GAS COMBUSTION CALCULATOR — namespace "gc-"
   simulators/gas-combustion/css/custom.css
   Component-specific styles not covered by the shared simulator.css
   generics (.sim-panel, .sim-field, .btn-primary, .sim-result-card…).
   Uses base.css design tokens — no hardcoded colors.
   ════════════════════════════════════════════════════════════════ */

/* ── Formula input (monospace) ─────────────────────────────────── */
.gc-input-mono {
    font-family: var(--font-mono);
    letter-spacing: .03em;
}

.gc-input--error {
    border-color: var(--color-danger) !important;
}

/* Parsed chips row (C, H, O, molar mass) */
.gc-parsed-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(110px, 1fr));
    gap: var(--space-sm);
    margin-top: var(--space-md);
}

.gc-parsed-item {
    display: flex;
    flex-direction: column;
    gap: 2px;
    padding: var(--space-sm) var(--space-md);
    background: var(--bg-hover);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
}

.gc-parsed-item__label {
    font-size: .68rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: .05em;
}

.gc-parsed-item__value {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--text-primary);
    font-family: var(--font-mono);
}

.gc-parsed-item__unit {
    font-size: .65rem;
    color: var(--text-muted);
    font-family: var(--font-mono);
}

/* ── Gas analysis grid ──────────────────────────────────────────── */
.gc-gas-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: var(--space-md);
}

.gc-gas-grid .sim-field {
    margin-bottom: 0;
}

/* Sum row */
.gc-gas-sum-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-sm) var(--space-md);
    background: var(--bg-hover);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    margin-top: var(--space-md);
    font-size: .8rem;
}

.gc-gas-sum-row span:first-child {
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: .04em;
    font-size: .7rem;
}

#gc-gas-sum {
    font-family: var(--font-mono);
    font-weight: 700;
    color: var(--text-primary);
}

#gc-gas-sum.gc-sum--invalid {
    color: var(--color-danger);
}

.gc-warning-msg {
    font-size: .78rem;
    color: var(--color-warning);
    background: rgba(217, 119, 6, .1);
    border: 1px solid rgba(217, 119, 6, .3);
    border-radius: var(--radius-md);
    padding: var(--space-sm) var(--space-md);
    margin-top: var(--space-sm);
    display: none;
}

.gc-warning-msg.is-visible {
    display: block;
}

/* ── Diagnostic badge ───────────────────────────────────────────── */
.gc-diagnostic {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-lg);
    border-radius: var(--radius-md);
    border: 1px solid var(--border);
    margin-bottom: var(--space-lg);
    font-size: .9rem;
    font-weight: 500;
}

.gc-diagnostic__text {
    font-weight: 600;
}

.gc-diagnostic__value {
    margin-left: auto;
    font-family: var(--font-mono);
    font-weight: 700;
}

.gc-diagnostic--stoich {
    background: rgba(22, 163, 74, .08);
    border-color: rgba(22, 163, 74, .3);
    color: var(--color-success);
}

.gc-diagnostic--excess {
    background: rgba(37, 99, 235, .08);
    border-color: rgba(37, 99, 235, .3);
    color: var(--brand-accent);
}

.gc-diagnostic--deficit {
    background: rgba(217, 119, 6, .08);
    border-color: rgba(217, 119, 6, .3);
    color: var(--color-warning);
}

/* ── Products table ─────────────────────────────────────────────── */
.gc-table-wrap {
    overflow-x: auto;
    margin-top: var(--space-md);
}

.gc-table {
    width: 100%;
    border-collapse: collapse;
    font-size: .85rem;
}

.gc-table th,
.gc-table td {
    padding: var(--space-sm) var(--space-md);
    text-align: left;
    border-bottom: 1px solid var(--border);
}

.gc-table th {
    font-size: .7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .05em;
    color: var(--text-muted);
    background: var(--bg-hover);
}

.gc-table td {
    font-family: var(--font-mono);
    color: var(--text-primary);
}

.gc-table__formula {
    font-weight: 700;
}

.gc-table__origin {
    display: block;
    font-size: .68rem;
    font-family: var(--font-sans);
    font-weight: 400;
    color: var(--text-muted);
}

.gc-table tr.gc-row-total td {
    font-weight: 700;
    border-top: 2px solid var(--border-strong);
    border-bottom: none;
}

.gc-model-note {
    font-size: .78rem;
    color: var(--text-muted);
    font-style: italic;
    padding: var(--space-sm) var(--space-md);
    background: var(--bg-hover);
    border-left: 3px solid var(--border-strong);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    margin-top: var(--space-md);
}

/* ── Actions row ─────────────────────────────────────────────────── */
.gc-actions {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: var(--space-md);
}

.gc-actions .btn-primary,
.gc-actions .btn-secondary {
    margin-top: 0;
    width: auto;
    flex: 0 0 auto;
}

.gc-basis-note {
    font-size: .72rem;
    color: var(--text-muted);
    font-family: var(--font-mono);
    margin-left: auto;
}

@media (max-width: 480px) {
    .gc-actions {
        flex-direction: column;
        align-items: stretch;
    }

    .gc-actions .btn-primary,
    .gc-actions .btn-secondary {
        width: 100%;
    }

    .gc-basis-note {
        margin-left: 0;
        text-align: center;
    }
}


/* ----------------------------------------------------------------
   BALANCEADOR ECUACIONES (bal-)
   ---------------------------------------------------------------- */
/*
 * balanceador-ecuaciones.css
 * EngSim — Chemical Equation Balancer
 * ────────────────────────────────────────────────────────────────
 * Scoped styles for simulators/balanceador-ecuaciones/
 * Builds on top of assets/css/simulator.css tokens.
 *
 * TOKEN MAP (old IEM → new EngSim):
 *   --color-primary         → --brand-accent
 *   --color-primary-light   → rgba(37,99,235,.2)
 *   --color-surface         → --bg-card
 *   --color-surface-alt     → --bg-hover
 *   --color-border          → --border
 *   --color-text            → --text-primary
 *   --color-text-secondary  → --text-secondary
 *   --color-text-muted      → --text-muted
 *   --color-success         → --color-success
 *   --space-2 / 4 / 6 …    → --space-xs / sm / md / lg / xl
 *   --radius-md / lg        → --radius-md / lg
 *   --shadow-sm / md        → --shadow-sm / md
 *   --transition-*          → --transition
 *   --font-mono             → --font-mono  (same name)
 *   --font-size-*           → explicit values
 */

/* ══════════════════════════════════════════════════════════════
   MODE TABS  (above the two-panel layout)
   ══════════════════════════════════════════════════════════════ */
.bal-mode-tabs {
    display: flex;
    gap: var(--space-xs);
    margin-bottom: var(--space-md);
    border-bottom: 1px solid var(--border);
    padding-bottom: var(--space-xs);
}

.bal-tab-btn {
    padding: 8px 18px;
    font-size: .85rem;
    font-weight: 600;
    color: var(--text-secondary);
    background: none;
    border: none;
    border-radius: var(--radius-md) var(--radius-md) 0 0;
    cursor: pointer;
    transition: color var(--transition), background var(--transition);
    border-bottom: 2px solid transparent;
    margin-bottom: -1px;
    /* sits on the bottom border */
}

.bal-tab-btn:hover {
    color: var(--text-primary);
    background: var(--bg-hover);
}

.bal-tab-btn.active {
    color: var(--brand-accent);
    border-bottom-color: var(--brand-accent);
    background: none;
}

.bal-tab-btn:disabled {
    opacity: .4;
    cursor: not-allowed;
}

/* ══════════════════════════════════════════════════════════════
   TEXT INPUT (full-width, no unit badge)
   ══════════════════════════════════════════════════════════════ */
.sim-input--text {
    width: 100%;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    background: var(--bg-input);
    padding: 9px 12px;
    font-size: .9rem;
    font-family: var(--font-mono);
    color: var(--text-primary);
    outline: none;
    transition: border-color var(--transition), box-shadow var(--transition);
}

.sim-input--text::placeholder {
    color: var(--text-muted);
    font-family: var(--font-sans);
}

.sim-input--text:focus {
    border-color: var(--brand-accent);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, .12);
}

/* ══════════════════════════════════════════════════════════════
   INPUT ERROR
   Inline field validation now uses the global .sim-error component
   from assets/css/simulator.css (.sim-error + .is-visible toggle).
   The old .bal-input-error block has been removed.
   ══════════════════════════════════════════════════════════════ */

/* ══════════════════════════════════════════════════════════════
   EMPTY STATE
   ══════════════════════════════════════════════════════════════ */
.bal-empty-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 48px var(--space-lg);
    background: var(--bg-card);
    border: 1px dashed var(--border-strong);
    border-radius: var(--radius-lg);
    text-align: center;
    color: var(--text-muted);
}

.bal-empty-icon {
    font-size: 3rem;
    margin-bottom: var(--space-md);
    opacity: .5;
}

.bal-empty-state h3 {
    font-size: 1rem;
    font-weight: 700;
    color: var(--text-secondary);
    margin-bottom: var(--space-xs);
}

.bal-empty-state p {
    font-size: .85rem;
    line-height: 1.6;
}

/* ══════════════════════════════════════════════════════════════
   ACTIVE EQUATION DISPLAY
   ══════════════════════════════════════════════════════════════ */
.bal-equation-panel {
    position: sticky;
    top: calc(var(--nav-h) + var(--space-sm));
    z-index: 10;
    border-color: rgba(37, 99, 235, .25);
    box-shadow: var(--shadow-md);
}

.bal-equation-string {
    font-family: var(--font-mono);
    font-size: clamp(1.1rem, 3vw, 1.6rem);
    font-weight: 700;
    color: var(--brand-accent);
    letter-spacing: .04em;
    padding: var(--space-sm) 0;
    word-break: break-all;
}

/* ══════════════════════════════════════════════════════════════
   MOLECULAR VIEW
   ══════════════════════════════════════════════════════════════ */
.bal-molecular-container {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-wrap: wrap;
    gap: var(--space-sm);
    padding: var(--space-sm) 0;
    min-height: 60px;
    overflow-x: auto;
    border-top: 1px solid var(--border);
}

.molecule-group {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    padding: 6px var(--space-sm);
    background: var(--bg-hover);
    border-radius: var(--radius-md);
    border: 1px solid var(--border);
    transition: box-shadow var(--transition);
}

.molecule-group:hover {
    box-shadow: var(--shadow-sm);
}

.molecule-coeff {
    font-family: var(--font-mono);
    font-weight: 700;
    font-size: 1.1rem;
    color: var(--text-secondary);
    min-width: 12px;
}

.atom-svg {
    transition: transform var(--transition);
}

.atom-svg:hover {
    transform: scale(1.15);
}

/*
 * ATOM COLOURS — CPK / Jmol conventional palette
 * ─────────────────────────────────────────────────────────────
 * These are intentional domain-specific constants, NOT UI theme
 * tokens. They follow the standard CPK/Jmol colour convention
 * used in chemistry visualisation worldwide and must NOT be
 * replaced with generic --brand-* or --color-* variables.
 *   H  → white/light-gray   C  → dark-gray
 *   N  → blue               O  → red
 *   S  → yellow             Cl → green
 *   Fe → orange             Al → medium-gray
 */

/* Atom colours — Light mode */
.atom-circle {
    transition: fill var(--transition), stroke var(--transition);
}

.atom-h {
    fill: #f3f4f6;    /* CPK H — white/light gray */
    stroke: #d1d5db;
}

.atom-c {
    fill: #4b5563;    /* CPK C — dark gray */
    stroke: #374151;
}

.atom-n {
    fill: #3b82f6;    /* CPK N — blue */
    stroke: #2563eb;
}

.atom-o {
    fill: #ef4444;    /* CPK O — red */
    stroke: #dc2626;
}

.atom-s {
    fill: #fde047;    /* CPK S — yellow */
    stroke: #eab308;
}

.atom-cl {
    fill: #22c55e;    /* CPK Cl — green */
    stroke: #16a34a;
}

.atom-fe {
    fill: #f97316;    /* CPK Fe — orange */
    stroke: #ea580c;
}

.atom-al {
    fill: #9ca3af;    /* CPK Al — medium gray */
    stroke: #6b7280;
}

.atom-default {
    fill: #a855f7;    /* CPK generic — purple */
    stroke: #9333ea;
}

/* Atom colours — Dark mode overrides */
body.dark .atom-h {
    fill: #374151;
    stroke: #4b5563;
}

body.dark .atom-c {
    fill: #9ca3af;
    stroke: #d1d5db;
}

body.dark .atom-n {
    fill: #2563eb;
    stroke: #60a5fa;
}

body.dark .atom-o {
    fill: #dc2626;
    stroke: #f87171;
}

body.dark .atom-s {
    fill: #ca8a04;
    stroke: #fde047;
}

body.dark .atom-cl {
    fill: #16a34a;
    stroke: #4ade80;
}

body.dark .atom-fe {
    fill: #ea580c;
    stroke: #fb923c;
}

body.dark .atom-al {
    fill: #6b7280;
    stroke: #9ca3af;
}

body.dark .atom-default {
    fill: #9333ea;
    stroke: #c084fc;
}

/* ══════════════════════════════════════════════════════════════
   STEP TIMELINE (Learning Mode)
   ══════════════════════════════════════════════════════════════ */
.bal-timeline-container {
    position: relative;
    padding-left: var(--space-lg);
}

.bal-timeline-container::before {
    content: '';
    position: absolute;
    left: 11px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--border);
}

.bal-step-card {
    position: relative;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: var(--space-md);
    margin-bottom: var(--space-md);
    opacity: .45;
    filter: grayscale(.8);
    transition: opacity var(--transition), filter var(--transition),
        border-color var(--transition), box-shadow var(--transition);
}

.bal-step-card.active {
    opacity: 1;
    filter: none;
    border-color: rgba(37, 99, 235, .35);
    box-shadow: var(--shadow-sm);
}

.bal-step-card.completed {
    opacity: .75;
    filter: none;
}

.bal-step-marker {
    position: absolute;
    left: calc(var(--space-lg) * -1 - 12px);
    top: 18px;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: var(--bg-card);
    border: 2px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 11px;
    font-weight: 700;
    z-index: 2;
    transition: background var(--transition), border-color var(--transition);
}

.bal-step-card.active .bal-step-marker {
    border-color: var(--brand-accent);
    background: var(--brand-accent);
    color: var(--text-on-accent);
}

.bal-step-card.completed .bal-step-marker {
    border-color: var(--color-success);
    background: var(--color-success);
    color: var(--text-on-accent);
}

.bal-step-header {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    margin-bottom: var(--space-xs);
}

.bal-step-icon {
    font-size: 1.1rem;
}

.bal-step-title {
    font-size: .9rem;
    font-weight: 700;
    color: var(--text-primary);
    margin: 0;
}

.bal-step-body {
    font-size: .82rem;
    color: var(--text-secondary);
    line-height: 1.65;
}

.bal-step-body strong {
    color: var(--text-primary);
}

/* Step navigation controls */
.bal-step-controls {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-md);
    margin-top: var(--space-md);
    padding-top: var(--space-md);
    border-top: 1px solid var(--border);
}

.bal-btn-next {
    margin-top: 0;
    /* override btn-primary default top margin */
    width: auto;
    padding: 9px var(--space-lg);
}

/* ══════════════════════════════════════════════════════════════
   ATOM COUNT TABLE
   ══════════════════════════════════════════════════════════════ */
.bal-table-wrapper {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.bal-count-table {
    width: 100%;
    border-collapse: collapse;
    font-size: .85rem;
}

.bal-count-table th,
.bal-count-table td {
    padding: var(--space-sm) var(--space-md);
    text-align: left;
    border-bottom: 1px solid var(--border);
}

.bal-count-table th {
    font-size: .72rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .06em;
    color: var(--text-muted);
    background: var(--bg-hover);
}

.bal-count-table td:nth-child(2),
.bal-count-table td:nth-child(3) {
    text-align: center;
    font-family: var(--font-mono);
    font-weight: 600;
    color: var(--text-primary);
}

.bal-count-table tr:last-child td {
    border-bottom: none;
}

/* Status pills */
.count-pill {
    display: inline-block;
    padding: 2px 10px;
    border-radius: 99px;
    font-size: .7rem;
    font-weight: 700;
    font-family: var(--font-mono);
    white-space: nowrap;
}

.pill-balanced {
    background: rgba(22, 163, 74, .1);
    color: #15803d;
}

.pill-unbalanced {
    background: rgba(220, 38, 38, .1);
    color: #b91c1c;
}

.pill-excess {
    background: rgba(37, 99, 235, .1);
    color: #1d4ed8;
}

body.dark .pill-balanced {
    background: rgba(22, 163, 74, .2);
    color: #4ade80;
}

body.dark .pill-unbalanced {
    background: rgba(220, 38, 38, .2);
    color: #f87171;
}

body.dark .pill-excess {
    background: rgba(37, 99, 235, .2);
    color: #93c5fd;
}

/* ══════════════════════════════════════════════════════════════
   TRAINING MODE — coefficient inputs
   ══════════════════════════════════════════════════════════════ */
.bal-training-grid {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: center;
    gap: var(--space-md);
    padding: var(--space-sm) 0;
}

.training-input-group {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    font-family: var(--font-mono);
    font-size: 1rem;
}

.training-coeff-input {
    width: 58px;
    height: 40px;
    text-align: center;
    font-size: 1rem;
    font-weight: 700;
    font-family: var(--font-mono);
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    background: var(--bg-input);
    color: var(--text-primary);
    transition: border-color var(--transition), box-shadow var(--transition);
}

.training-coeff-input:focus {
    outline: none;
    border-color: var(--brand-accent);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, .12);
}

/* Feedback panel */
.bal-feedback-panel {
    margin-top: var(--space-md);
    padding: var(--space-md);
    border-radius: var(--radius-md);
    font-size: .85rem;
    line-height: 1.6;
}

.bal-feedback-correct {
    background: rgba(22, 163, 74, .08);
    border: 1px solid rgba(22, 163, 74, .3);
    color: #15803d;
}

.bal-feedback-incorrect {
    background: rgba(220, 38, 38, .07);
    border: 1px solid rgba(220, 38, 38, .25);
    color: #b91c1c;
}

body.dark .bal-feedback-correct {
    background: rgba(22, 163, 74, .15);
    color: #4ade80;
    border-color: rgba(74, 222, 128, .3);
}

body.dark .bal-feedback-incorrect {
    background: rgba(220, 38, 38, .15);
    color: #f87171;
    border-color: rgba(248, 113, 113, .3);
}

.feedback-hint {
    margin-top: var(--space-xs);
    font-style: italic;
    opacity: .85;
}

/* ══════════════════════════════════════════════════════════════
   EXERCISE BANK — topic filters + example buttons
   ══════════════════════════════════════════════════════════════ */
.bal-topic-filters {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-xs);
    margin-bottom: var(--space-md);
}

.bal-filter-chip {
    padding: 4px 12px;
    border-radius: 99px;
    font-size: .72rem;
    font-weight: 600;
    cursor: pointer;
    font-family: inherit;
    border: 1px solid var(--border);
    transition: background var(--transition), color var(--transition), border-color var(--transition);
    background: var(--bg-hover);
    color: var(--text-secondary);
}

.bal-filter-chip:hover,
.bal-filter-chip.active {
    background: var(--brand-accent);
    color: var(--text-on-accent);
    border-color: var(--brand-accent);
}

.bal-example-btns {
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
}

.bal-example-btn {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    padding: var(--space-sm) var(--space-md);
    background: var(--bg-hover);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    cursor: pointer;
    text-align: left;
    transition: border-color var(--transition), background var(--transition), transform var(--transition);
}

.bal-example-btn:hover {
    background: var(--bg-card);
    border-color: var(--brand-accent);
    transform: translateX(3px);
}

.bal-example-title {
    font-size: .82rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 2px;
}

.bal-example-formula {
    font-family: var(--font-mono);
    font-size: .72rem;
    color: var(--text-muted);
}

.bal-example-meta {
    display: flex;
    justify-content: space-between;
    width: 100%;
    margin-top: var(--space-xs);
    font-size: .68rem;
    text-transform: uppercase;
    letter-spacing: .04em;
}

.bal-example-diff {
    font-weight: 700;
    color: var(--brand-accent);
}


/* ----------------------------------------------------------------
   MOHR CIRCLE (mohr-)
   ---------------------------------------------------------------- */
/* ============================================================
   custom.css — Mohr's Circle Calculator
   Simulator-specific styles only. Anything shared across
   simulators belongs in assets/css/simulator.css instead.
   engsim.app
   ============================================================ */

/* The plot canvases render their own dark theme (see js/plot.js THEME.bg)
   regardless of the site's light/dark mode, so they need a bit more room
   than the default .sim-chart-wrap canvas cap (260px) — the circle needs
   height to stay legible. */
#sim-chart {
    width: 100%;
    height: min(380px, 75vw);
    max-height: none;
    display: block;
}

#sim-chart-element {
    width: 100%;
    height: 260px;
    max-height: none;
    display: block;
}

/* ── Angle slider (θ) ─────────────────────────────────────────── */
.sim-slider-row {
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

.sim-slider-row input[type="range"] {
    flex: 1;
    accent-color: var(--brand-accent);
}

.sim-slider-value {
    min-width: 60px;
    text-align: right;
    font-family: var(--font-mono);
    font-weight: 700;
    color: var(--brand-accent);
    font-size: .9rem;
}

/* ── Hydrostatic-state badge on the results header ─────────────── */
.sim-panel__badge--info {
    background: rgba(37, 99, 235, .12);
    color: var(--brand-accent);
}

/* ── Chart header (label + fullscreen button) ───────────────────── */
.sim-chart-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-xs);
}

.sim-chart-header .sim-chart-label {
    margin-bottom: 0;
}

.sim-chart-fullscreen-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 26px;
    height: 26px;
    padding: 0;
    background: transparent;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    color: var(--text-muted);
    cursor: pointer;
    transition: background var(--transition), color var(--transition);
}

.sim-chart-fullscreen-btn:hover {
    background: var(--bg-card);
    color: var(--brand-accent);
}

.sim-chart-fullscreen-btn .icon-collapse {
    display: none;
}

.sim-chart-fullscreen-btn.is-fullscreen .icon-expand {
    display: none;
}

.sim-chart-fullscreen-btn.is-fullscreen .icon-collapse {
    display: block;
}

/* ── Fullscreen mode ──────────────────────────────────────────────
   The plot canvases keep their own dark theme (js/plot.js THEME.bg)
   in fullscreen too, regardless of the site's light/dark mode. */
.sim-chart-wrap:fullscreen,
.sim-chart-wrap:-webkit-full-screen {
    display: flex;
    flex-direction: column;
    background: var(--bg-page);
    padding: var(--space-lg);
}

.sim-chart-wrap:fullscreen .sim-chart-header,
.sim-chart-wrap:-webkit-full-screen .sim-chart-header {
    flex-shrink: 0;
}

.sim-chart-wrap:fullscreen .sim-chart-label,
.sim-chart-wrap:-webkit-full-screen .sim-chart-label {
    color: var(--text-secondary);
}

.sim-chart-wrap:fullscreen .sim-chart-fullscreen-btn,
.sim-chart-wrap:-webkit-full-screen .sim-chart-fullscreen-btn {
    border-color: var(--border);
    color: var(--text-primary);
}

.sim-chart-wrap:fullscreen #sim-chart,
.sim-chart-wrap:-webkit-full-screen #sim-chart,
.sim-chart-wrap:fullscreen #sim-chart-element,
.sim-chart-wrap:-webkit-full-screen #sim-chart-element {
    flex: 1;
    width: 100%;
    height: 100%;
    max-height: none;
}

/* Mobile responsive adjustments */
@media (max-width: 640px) {
    #sim-chart {
        max-height: 260px;
    }

    #sim-chart-element {
        max-height: 180px;
    }
}


/* ----------------------------------------------------------------
   CHEMICAL REACTIONS (chr-)
   ---------------------------------------------------------------- */
/* ============================================================
   simulator.css — Chemical Reactions Simulator
   Scoped styles for THIS simulator only. Reuses the shared
   .sim-* / .edu-* / .status-banner components from
   assets/css/simulator.css — only genuinely chemistry-specific
   pieces live here (reactant rows, redox cards, electron flow,
   the local module tabs).
   engsim.app
   ============================================================ */

/* ── Local module tabs (not part of the shared .sim-* system) ── */
.chem-tabs {
    display: flex;
    gap: var(--space-sm);
    margin-bottom: var(--space-lg);
    border-bottom: 2px solid var(--border);
    overflow-x: auto;
    overflow-y: hidden;
    -webkit-overflow-scrolling: touch;
}

.chem-tab-btn {
    padding: var(--space-sm) var(--space-lg);
    background: none;
    border: none;
    border-bottom: 3px solid transparent;
    margin-bottom: -2px;
    font-family: var(--font-sans);
    font-size: .875rem;
    font-weight: 600;
    color: var(--text-muted);
    cursor: pointer;
    transition: color var(--transition), background var(--transition);
    border-radius: var(--radius-sm) var(--radius-sm) 0 0;
    white-space: nowrap;
    flex-shrink: 0;
}

.chem-tab-btn:hover {
    color: var(--brand-accent);
    background: var(--bg-hover);
}

.chem-tab-btn.active {
    color: var(--brand-accent);
    border-bottom-color: var(--brand-accent);
}

/* ── Training-mode toggle switch ───────────────────────────────── */
.mode-toggle-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: var(--space-md);
    margin-bottom: var(--space-md);
    padding-bottom: var(--space-md);
    border-bottom: 1px solid var(--border);
}

.mode-label { font-size: .8rem; font-weight: 600; color: var(--text-primary); }

.mode-toggle-container .switch { position: relative; display: inline-block; width: 38px; height: 20px; }
.mode-toggle-container .switch input { opacity: 0; width: 0; height: 0; }

.mode-toggle-container .slider {
    position: absolute; inset: 0;
    background: var(--border-strong);
    border-radius: 20px;
    cursor: pointer;
    transition: background .2s ease;
}

.mode-toggle-container .slider::before {
    content: '';
    position: absolute;
    width: 14px; height: 14px;
    left: 3px; bottom: 3px;
    background: #fff;
    border-radius: 50%;
    transition: transform .2s ease;
}

.mode-toggle-container .switch input:checked + .slider { background: var(--brand-accent); }
.mode-toggle-container .switch input:checked + .slider::before { transform: translateX(18px); }
.mode-toggle-container .switch input:disabled + .slider { opacity: .5; cursor: not-allowed; }

/* ── Reactant rows (dynamic, limiting-reagent module) ───────────── */
.reactant-rows-title {
    font-size: .72rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .08em;
    color: var(--text-muted);
    margin-bottom: var(--space-xs);
}

.reactants-placeholder {
    color: var(--text-muted);
    font-size: .875rem;
    font-style: italic;
    padding: var(--space-sm) 0;
}

.example-btns { display: flex; flex-wrap: wrap; gap: var(--space-xs); }

.reactant-row {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) 0;
    border-bottom: 1px solid var(--border);
}

.reactant-row:last-child { border-bottom: none; }

.reactant-row__label { flex: 0 0 auto; min-width: 100px; }

.reactant-formula {
    display: block;
    font-family: var(--font-mono);
    font-size: 1rem;
    font-weight: 700;
    color: var(--brand-accent);
}

.reactant-mass {
    display: block;
    font-size: .72rem;
    color: var(--text-muted);
    margin-top: 2px;
}

/* Reuses .sim-input / .sim-select for consistent look, custom layout.
   min-width: 0 overrides the flex-item default (min-width: auto),
   which otherwise refuses to shrink below the content's natural
   width and pushes the unit <select> outside the panel. */
.reactant-row__input { display: flex; gap: var(--space-xs); flex: 1; min-width: 0; }
.reactant-row__input .sim-input {
    flex: 1;
    min-width: 80px;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    background: var(--bg-input);
}
.reactant-row__input .sim-select { flex: 0 0 78px; min-width: 78px; padding-right: 28px; }

@media (max-width: 420px) {
    .reactant-row { flex-direction: column; align-items: stretch; gap: var(--space-xs); }
    .reactant-row__label { min-width: 0; }
}

/* ── Conversion / ratio table cells ────────────────────────────── */
.ratio-cell { font-family: var(--font-mono); font-weight: 800; }
.conversion-eq { font-family: var(--font-mono); max-width: 280px; }

.limiting-row td { background: rgba(220, 38, 38, .04); }
.limiting-row .ratio-cell { color: var(--color-danger); }

.limiting-badge {
    display: inline-block;
    padding: 3px 8px;
    background: rgba(220, 38, 38, .08);
    border: 1px solid rgba(220, 38, 38, .3);
    border-radius: 99px;
    font-size: 10px;
    font-weight: 700;
    text-transform: uppercase;
    color: var(--color-danger);
    letter-spacing: .05em;
}

.excess-badge {
    display: inline-block;
    padding: 3px 8px;
    background: rgba(22, 163, 74, .08);
    border: 1px solid rgba(22, 163, 74, .3);
    border-radius: 99px;
    font-size: 10px;
    font-weight: 700;
    text-transform: uppercase;
    color: var(--color-success);
    letter-spacing: .05em;
}

body.dark .limiting-badge { color: #fca5a5; }
body.dark .excess-badge { color: #86efac; }

.ratio-explanation {
    margin-top: var(--space-md);
    font-size: .875rem;
    color: var(--text-secondary);
    line-height: 1.6;
    padding: var(--space-sm) var(--space-md);
    background: var(--bg-hover);
    border-radius: var(--radius-md);
    border-left: 3px solid var(--brand-accent);
}

/* Result-table (generic table, not in the shared file — used for
   the conversion & ratio tables which need row-level highlighting
   that .edu-table doesn't provide) */
.chem-table-scroll { overflow-x: auto; overflow-y: hidden; -webkit-overflow-scrolling: touch; }

.result-table { width: 100%; border-collapse: collapse; font-size: .875rem; }

.result-table th {
    text-align: left;
    padding: var(--space-sm);
    font-size: .72rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .06em;
    color: var(--text-muted);
    background: var(--bg-hover);
    border-bottom: 2px solid var(--border);
    white-space: nowrap;
}

.result-table td {
    padding: var(--space-sm);
    border-bottom: 1px solid var(--border);
    color: var(--text-primary);
    vertical-align: middle;
}

.result-table tr:last-child td { border-bottom: none; }
.result-table tr:hover td { background: rgba(37, 99, 235, .03); }

.formula-cell {
    font-family: var(--font-mono);
    font-weight: 700;
    color: var(--brand-accent);
}

/* Result-section wrapper (groups a numbered step + its content) */
.result-section { margin-bottom: var(--space-lg); }
.result-section:last-child { margin-bottom: 0; }

.result-section__title {
    font-size: .85rem;
    font-weight: 700;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: .06em;
    margin: 0 0 var(--space-md);
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    flex-wrap: wrap;
}

.step-number {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 22px; height: 22px;
    background: var(--brand-accent);
    color: #fff;
    border-radius: 50%;
    font-size: 11px;
    font-weight: 700;
    flex-shrink: 0;
}

.section-note {
    font-size: .72rem;
    font-weight: 400;
    color: var(--text-muted);
    margin-left: auto;
}

/* ── Equation display / comparison ─────────────────────────────── */
.equation-display {
    background: var(--bg-hover);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: var(--space-md) var(--space-lg);
}

.equation-string {
    font-family: var(--font-mono);
    font-size: 1.25rem;
    color: var(--brand-accent);
    font-weight: 700;
}

.equation-comparison { display: flex; flex-direction: column; gap: var(--space-xs); }
.eq-comp-item { display: flex; align-items: baseline; gap: var(--space-xs); flex-wrap: wrap; }

.eq-comp-label {
    font-size: .72rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .06em;
    color: var(--text-muted);
    flex-shrink: 0;
}

.eq-comp-str { font-family: var(--font-mono); font-size: 1rem; }
.eq-comp-str.highlight { color: var(--brand-accent); font-weight: 700; }

/* ── Result-card colour variants (extends .sim-result-card) ─────── */
.sim-result-card--limiting { background: rgba(220, 38, 38, .06); border-color: rgba(220, 38, 38, .25); }
.sim-result-card--limiting .sim-result-value { color: var(--color-danger); }
.sim-result-card--product  { background: rgba(22, 163, 74, .06); border-color: rgba(22, 163, 74, .25); }
.sim-result-card--product  .sim-result-value { color: var(--color-success); }
.sim-result-card--excess   { background: rgba(37, 99, 235, .06); border-color: rgba(37, 99, 235, .2); }

/* ── Quiz / training mode reveal ───────────────────────────────── */
.quiz-hidden .sim-result-value,
.quiz-hidden .sim-result-unit { display: none !important; }

.quiz-prompt {
    margin-bottom: var(--space-lg);
    padding: var(--space-md);
    background: var(--bg-hover);
    border-radius: var(--radius-md);
    border: 1px dashed var(--border-strong);
    text-align: center;
}

.quiz-question { font-weight: 700; color: var(--text-primary); margin-bottom: var(--space-sm); }
.quiz-reveal-btn { margin: 0 auto; }

/* ── Bar chart visualisation (inside .sim-chart-wrap) ──────────── */
.bar-chart { display: flex; flex-direction: column; gap: var(--space-md); }
.bar-row { display: flex; flex-direction: column; gap: var(--space-xs); }
.bar-label { display: flex; align-items: center; gap: var(--space-xs); flex-wrap: wrap; }

.bar-formula {
    font-family: var(--font-mono);
    font-weight: 700;
    color: var(--text-primary);
    font-size: .875rem;
}

.bar-track {
    height: 28px;
    background: var(--bg-card);
    border-radius: var(--radius-sm);
    overflow: hidden;
    display: flex;
    border: 1px solid var(--border);
}

.bar-segment { height: 100%; transition: width .7s cubic-bezier(.4,0,.2,1); }
.bar-consumed { background: var(--color-warning); }
.bar-row--limiting .bar-consumed { background: var(--color-danger); }
.bar-leftover { background: var(--color-success); }

.bar-legend { display: flex; gap: var(--space-md); flex-wrap: wrap; color: var(--text-muted); font-size: .8rem; }
.legend-consumed { color: var(--color-warning); }
.bar-row--limiting .legend-consumed { color: var(--color-danger); }
.legend-leftover { color: var(--color-success); }

/* ── Redox — header & final equation ───────────────────────────── */
.redox-header {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    flex-wrap: wrap;
    margin-bottom: var(--space-md);
}

.redox-title { font-size: 1rem; font-weight: 700; color: var(--text-primary); margin: 0; }

/* Extensions for .edu-process-badge */
.edu-process-badge--acidic {
    background: rgba(217, 119, 6, .1);
    color: var(--color-warning);
    border: 1px solid rgba(217, 119, 6, .35);
}

.edu-process-badge--basic {
    background: rgba(37, 99, 235, .1);
    color: var(--brand-accent);
    border: 1px solid rgba(37, 99, 235, .35);
}

body.dark .edu-process-badge--acidic { color: #fde68a; }
body.dark .edu-process-badge--basic  { color: #bfdbfe; }

.final-equation-box {
    margin-bottom: var(--space-lg);
    padding: var(--space-md) var(--space-lg);
    background: var(--bg-hover);
    border-left: 4px solid var(--brand-accent);
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
}

.final-equation-label {
    display: block;
    font-size: .72rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .08em;
    color: var(--text-muted);
    margin-bottom: var(--space-xs);
}

.final-equation-str {
    font-family: var(--font-mono);
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--brand-accent);
    word-break: break-word;
}

/* ── Redox — oxidation numbers table ───────────────────────────── */
.ox-number { font-family: var(--font-mono); font-weight: 800; font-size: 1rem; color: var(--brand-accent); }

/* ── Redox — identification cards ──────────────────────────────── */
.redox-identification {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-md);
}

@media (max-width: 500px) {
    .redox-identification { grid-template-columns: 1fr; }
}

.redox-id-card { padding: var(--space-lg); border-radius: var(--radius-md); border: 1px solid; }

.id-oxidation { background: rgba(239, 68, 68, .08); border-color: rgba(239, 68, 68, .3); }
.id-reduction { background: rgba(37, 99, 235, .08); border-color: rgba(37, 99, 235, .3); }

.id-card__label {
    font-size: .72rem;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: .1em;
    margin-bottom: var(--space-xs);
}

.id-oxidation .id-card__label { color: #b91c1c; }
.id-reduction .id-card__label { color: #1d4ed8; }

.id-card__species {
    font-family: var(--font-mono);
    font-size: 1.25rem;
    font-weight: 800;
    color: var(--text-primary);
    margin-bottom: var(--space-xs);
}

.id-card__change {
    font-family: var(--font-mono);
    font-size: .875rem;
    color: var(--text-muted);
    margin-bottom: var(--space-xs);
}

.id-card__note { font-size: .875rem; color: var(--text-primary); margin-bottom: var(--space-xs); }
.id-card__agent { font-size: .75rem; color: var(--text-muted); font-style: italic; }

/* ── Electron flow animation ────────────────────────────────────── */
.electron-flow {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-md);
    background: var(--bg-hover);
    border-radius: var(--radius-md);
    flex-wrap: wrap;
}

.ef-species {
    font-family: var(--font-mono);
    font-size: 1.1rem;
    font-weight: 800;
    padding: var(--space-xs) var(--space-md);
    border-radius: var(--radius-md);
    white-space: nowrap;
}

.ef-oxidation { background: rgba(239, 68, 68, .08); border: 1px solid rgba(239, 68, 68, .3); color: #b91c1c; }
.ef-reduction { background: rgba(37, 99, 235, .08); border: 1px solid rgba(37, 99, 235, .3); color: #1d4ed8; }

.ef-arrow-container {
    flex: 1;
    min-width: 140px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-xs);
}

.ef-arrow { position: relative; width: 100%; display: flex; align-items: center; }
.ef-svg { width: 100%; height: 40px; }

.ef-electrons {
    position: absolute;
    top: 50%;
    left: -8px;
    transform: translateY(-50%);
    font-family: var(--font-mono);
    font-size: .72rem;
    font-weight: 800;
    color: var(--brand-accent);
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 99px;
    padding: 2px 6px;
    animation: slideAlongArrow 2.5s ease-in-out infinite;
    white-space: nowrap;
}

@keyframes slideAlongArrow {
    0%   { left: 0%;   opacity: 0; }
    10%  { opacity: 1; }
    90%  { opacity: 1; }
    100% { left: 85%;  opacity: 0; }
}

.ef-label { text-align: center; font-size: .8rem; color: var(--text-muted); }

/* ── Redox step-by-step breakdown ──────────────────────────────── */
.steps-toggle-btn {
    margin-left: auto;
    padding: 4px 12px;
    background: none;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    font-family: var(--font-sans);
    font-size: .72rem;
    font-weight: 600;
    color: var(--text-muted);
    cursor: pointer;
    transition: color var(--transition), border-color var(--transition);
}

.steps-toggle-btn:hover { color: var(--brand-accent); border-color: var(--brand-accent); }

.steps-container { display: flex; flex-direction: column; margin-top: var(--space-sm); }

/* Extensions for .edu-example to handle step variants */
.edu-example--info      { border-left-color: var(--brand-accent); }
.edu-example--info .edu-example__title { color: var(--brand-accent); }

/* Note: Redox conventions dictate Oxidation = Red, Reduction = Blue. 
   These hex values are domain-specific pedagogical conventions. */
.edu-example--oxidation { border-left-color: #dc2626; }
.edu-example--oxidation .edu-example__title { color: #b91c1c; }

.edu-example--reduction { border-left-color: #1d4ed8; }
.edu-example--reduction .edu-example__title { color: #1d4ed8; }

.edu-example--combined  { border-left-color: var(--color-success); }
.edu-example--combined .edu-example__title { color: var(--color-success); }

body.dark .edu-example--oxidation .edu-example__title { color: #fca5a5; }
body.dark .edu-example--reduction .edu-example__title { color: #93c5fd; }
body.dark .edu-example--combined  .edu-example__title { color: #86efac; }

.step-line { font-family: var(--font-mono); font-size: .875rem; color: var(--text-primary); line-height: 1.8; }



/* ----------------------------------------------------------------
   VOLTAGE DIVIDER (vd-)
   ---------------------------------------------------------------- */
/**
 * custom.css — Voltage Divider — Simulator-specific styles
 * engsim.app
 *
 * Everything here is scoped to THIS simulator only. Shared look and
 * feel (panels, inputs, buttons, results cards, validation shake,
 * .is-hidden) already comes from base.css / simulator.css — this
 * file only adds what those don't cover: mode tabs, the design-mode
 * toggle switch, fixed-resistor radio cards, the dynamic resistor
 * list, the breakdown table, and result-card overload warnings.
 * ─────────────────────────────────────────────────────────────────
 */

/* ── Mode tabs (Two-Resistor / Series Chain) ─────────────────────── */
.mode-tabs {
  display: flex;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
}

.mode-tab {
  flex: 1;
  padding: 10px var(--space-md);
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text-secondary);
  font-size: .8rem;
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition), color var(--transition), border-color var(--transition);
}

.mode-tab:hover {
  border-color: var(--brand-accent);
}

.mode-tab.is-active {
  background: var(--brand-accent);
  border-color: var(--brand-accent);
  color: var(--text-on-accent);
}

/* ── Design mode toggle row ───────────────────────────────────────── */
.design-toggle-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  padding: var(--space-sm) var(--space-md);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-md);
  background: var(--bg-hover);
}

.design-toggle-row label {
  font-size: .8rem;
  font-weight: 600;
  color: var(--text-primary);
  cursor: pointer;
}

.design-toggle-row p {
  margin: 2px 0 0;
  font-size: .73rem;
  color: var(--text-muted);
}

.switch {
  position: relative;
  display: inline-block;
  width: 38px;
  height: 22px;
  flex-shrink: 0;
}

.switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.switch-track {
  position: absolute;
  inset: 0;
  background: var(--border-strong);
  border-radius: 99px;
  cursor: pointer;
  transition: background var(--transition);
}

.switch-track::before {
  content: '';
  position: absolute;
  left: 3px;
  top: 3px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--bg-card);
  transition: transform var(--transition);
}

.switch input:checked + .switch-track {
  background: var(--brand-accent);
}

.switch input:checked + .switch-track::before {
  transform: translateX(16px);
}

/* ── Fixed-resistor radio cards (design mode) ─────────────────────── */
.radio-card-group {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-sm);
  margin-bottom: var(--space-md);
}

.radio-card {
  position: relative;
  display: block;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: var(--space-sm) var(--space-md);
  cursor: pointer;
  transition: border-color var(--transition), background var(--transition);
}

.radio-card input {
  position: absolute;
  opacity: 0;
}

.radio-card__title {
  font-size: .8125rem;
  font-weight: 600;
  color: var(--text-primary);
}

.radio-card__desc {
  display: block;
  font-size: .7rem;
  color: var(--text-muted);
  margin-top: 2px;
}

/* Highlight the selected card. :has() is well supported in current
   evergreen browsers; on the rare browser without it the radio still
   works correctly, it just won't get the accent highlight. */
.radio-card:has(input:checked) {
  border-color: var(--brand-accent);
  background: rgba(37, 99, 235, .06);
}

/* Radio-card equivalent of .sim-input-wrap.sim-input--invalid —
   reuses the @keyframes sim-shake already defined in simulator.css. */
.radio-card.is-invalid {
  border-color: var(--color-danger);
  box-shadow: 0 0 0 3px rgba(220, 38, 38, .15);
  animation: sim-shake .4s ease-in-out;
}

/* Field that is currently being computed by design mode */
.sim-field.is-computed .sim-input {
  background: var(--bg-hover);
  color: var(--text-muted);
  cursor: not-allowed;
}

/* ── Dynamic resistor list (series chain mode) ─────────────────────
   Mirrors the static-beam load-list pattern: a clear visual separator
   between the "add" control and the list of rows. */
#resistor-list {
  border-top: 1px solid var(--border);
  margin-top: var(--space-md);
  padding-top: var(--space-md);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.resistor-row {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.resistor-row__label {
  flex-shrink: 0;
  width: 32px;
  font-size: .8rem;
  font-weight: 700;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.resistor-row .sim-input-wrap {
  flex: 1;
  margin-bottom: 0;
}

.resistor-row__remove {
  flex-shrink: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--color-danger);
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition);
}

.resistor-row__remove:hover {
  background: rgba(220, 38, 38, .08);
  border-color: var(--color-danger);
}

.resistor-row__remove:disabled {
  opacity: .35;
  cursor: not-allowed;
}

.chain-list-hint {
  font-size: .73rem;
  color: var(--text-muted);
  margin-top: var(--space-sm);
}

/* "+ Add resistor" reuses .btn-secondary but needs to span the panel */
.btn-add-resistor {
  width: 100%;
  justify-content: center;
}

/* ── Circuit diagram (SVG injected by diagram.js via simulator.js) ─── */
#circuit-diagram svg {
  display: block;
  width: 100%;
  height: auto;
  max-width: 260px;
  margin: 0 auto;
}
.breakdown-table-wrap {
  overflow-x: auto;
  margin-top: var(--space-md);
}

.breakdown-table {
  width: 100%;
  border-collapse: collapse;
  font-size: .8125rem;
}

.breakdown-table th,
.breakdown-table td {
  text-align: left;
  padding: var(--space-xs) var(--space-sm);
  border-bottom: 1px solid var(--border);
  font-family: var(--font-mono);
}

.breakdown-table th {
  font-size: .68rem;
  text-transform: uppercase;
  letter-spacing: .05em;
  color: var(--text-muted);
  font-family: var(--font-sans);
}

.breakdown-table tr.is-overload td {
  color: var(--color-danger);
}

.breakdown-table tr.is-overload td:last-child {
  font-weight: 700;
}

/* ── Power overload warning on result cards ─────────────────────────── */
.sim-result-warning {
  display: block;
  margin-top: 4px;
  font-size: .68rem;
  font-weight: 700;
  color: var(--color-danger);
}

.sim-result-warning:empty {
  display: none;
}