/* ══════════════════════════════════════════════════
   TimberShift — Wood Movement & Seasonal Expansion Calculator
   Design System: Warm Walnut & Sawdust Amber Theme
   ══════════════════════════════════════════════════ */

:root {
    --bg-primary: #140e0b;
    --bg-surface: #1e1612;
    --bg-surface-2: #2a1e19;
    --bg-surface-3: #382921;
    --border-color: #423026;
    --border-hover: #614739;
    
    --text-primary: #f5ebe0;
    --text-secondary: #d4c5b9;
    --text-muted: #968375;
    
    --accent: #d97706;
    --accent-hover: #f59e0b;
    --accent-glow: rgba(217, 119, 6, 0.18);
    --accent-glow-strong: rgba(245, 158, 11, 0.35);
    
    --wood-walnut: #3b2318;
    --wood-amber: #b45309;
    --wood-gold: #fbbf24;
    
    --status-expansion: #f59e0b;
    --status-contraction: #38bdf8;
    --status-stable: #22c55e;
    
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    
    --font-heading: 'Outfit', 'Inter', system-ui, sans-serif;
    --font-body: 'Inter', system-ui, sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
    
    --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-family: var(--font-body);
    line-height: 1.6;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.25rem 3rem;
}

/* ── Header ── */
.app-header {
    background: linear-gradient(180deg, #1c130e 0%, var(--bg-primary) 100%);
    border-bottom: 1px solid var(--border-color);
    padding: 2.5rem 1rem 2rem;
    text-align: center;
    margin-bottom: 1.5rem;
}

.header-container {
    max-width: 800px;
    margin: 0 auto;
}

.brand-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--bg-surface-2);
    border: 1px solid var(--border-color);
    border-radius: 50px;
    padding: 0.35rem 1rem;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--accent-hover);
    margin-bottom: 1rem;
    letter-spacing: 0.02em;
}

.app-header h1 {
    font-family: var(--font-heading);
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 800;
    color: var(--text-primary);
    letter-spacing: -0.02em;
    margin-bottom: 0.5rem;
}

.header-subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
    font-weight: 400;
}

/* ── Ad Placeholders ── */
.ad-placeholder {
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--bg-surface);
    border: 1px dashed var(--border-color);
    color: var(--text-muted);
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-radius: var(--radius-sm);
    margin: 1rem auto 1.5rem;
}

.ad-desktop {
    width: 728px;
    height: 90px;
}

.ad-mobile {
    display: none;
    width: 320px;
    height: 50px;
}

@media (max-width: 768px) {
    .ad-desktop { display: none; }
    .ad-mobile { display: flex; }
}

/* ── Grid Layout ── */
.calculator-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    margin-bottom: 3rem;
}

@media (max-width: 960px) {
    .calculator-grid {
        grid-template-columns: 1fr;
    }
}

/* ── Cards ── */
.calc-card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.75rem;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.4);
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 1rem;
}

.card-header h2 {
    font-family: var(--font-heading);
    font-size: 1.35rem;
    font-weight: 700;
    color: var(--text-primary);
}

/* ── Unit Toggle ── */
.unit-toggle {
    display: flex;
    background: var(--bg-surface-2);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 2px;
}

.btn-toggle {
    background: none;
    border: none;
    color: var(--text-muted);
    font-family: var(--font-body);
    font-size: 0.825rem;
    font-weight: 600;
    padding: 0.4rem 0.8rem;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: var(--transition);
}

.btn-toggle.active {
    background: var(--accent);
    color: #fff;
    box-shadow: 0 2px 8px var(--accent-glow);
}

/* ── Form Controls ── */
.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-group label {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.form-control {
    background: var(--bg-surface-2);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-family: var(--font-body);
    font-size: 1rem;
    padding: 0.75rem 1rem;
    transition: var(--transition);
    width: 100%;
}

.form-control:focus {
    outline: none;
    border-color: var(--accent-hover);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

.select-wrapper {
    position: relative;
}

.select-wrapper select {
    appearance: none;
    cursor: pointer;
    padding-right: 2.5rem;
}

.select-wrapper::after {
    content: '▾';
    position: absolute;
    right: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    pointer-events: none;
}

/* Custom Coeff Row */
.form-row.custom-coeffs {
    display: flex;
    gap: 1rem;
}

.form-group.half {
    flex: 1;
}

.hidden {
    display: none !important;
}

/* Grain Cut Selector */
.grain-selector {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.75rem;
}

@media (max-width: 600px) {
    .grain-selector {
        grid-template-columns: 1fr;
    }
}

.grain-card {
    background: var(--bg-surface-2);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 0.85rem;
    cursor: pointer;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    text-align: center;
    transition: var(--transition);
}

.grain-card input[type="radio"] {
    position: absolute;
    opacity: 0;
    pointer-events: none;
}

.grain-card:hover {
    border-color: var(--border-hover);
    background: var(--bg-surface-3);
}

.grain-card.active {
    border-color: var(--accent);
    background: var(--bg-surface-3);
    box-shadow: 0 0 0 2px var(--accent-glow);
}

.grain-icon {
    width: 42px;
    height: 42px;
    border-radius: 50%;
    border: 2px solid var(--border-color);
    background: #140e0b;
    position: relative;
    overflow: hidden;
}

.flat-grain::before {
    content: '';
    position: absolute;
    width: 100%;
    height: 100%;
    border-radius: 50%;
    border: 2px solid var(--wood-gold);
    top: 50%;
    left: 0;
}

.quarter-grain::before {
    content: '';
    position: absolute;
    width: 100%;
    height: 100%;
    background: repeating-linear-gradient(90deg, var(--wood-gold) 0, var(--wood-gold) 2px, transparent 2px, transparent 6px);
}

.rift-grain::before {
    content: '';
    position: absolute;
    width: 100%;
    height: 100%;
    background: repeating-linear-gradient(45deg, var(--wood-gold) 0, var(--wood-gold) 2px, transparent 2px, transparent 6px);
}

.grain-title {
    font-weight: 700;
    font-size: 0.875rem;
    color: var(--text-primary);
}

.grain-desc {
    font-size: 0.725rem;
    color: var(--text-muted);
}

/* Stepper Pills */
.input-with-stepper {
    display: flex;
    flex-direction: column;
    gap: 0.6rem;
}

.preset-pills {
    display: flex;
    gap: 0.5rem;
}

.pill-btn {
    background: var(--bg-surface-2);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-family: var(--font-mono);
    font-size: 0.8rem;
    padding: 0.3rem 0.65rem;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: var(--transition);
}

.pill-btn:hover {
    border-color: var(--accent);
    color: var(--text-primary);
}

.pill-btn.active {
    background: var(--accent-glow);
    border-color: var(--accent);
    color: var(--accent-hover);
    font-weight: 600;
}

/* Section Divider */
.form-section-divider {
    display: flex;
    align-items: center;
    margin: 0.5rem 0;
    color: var(--text-muted);
    font-size: 0.8rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

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

.form-section-divider span {
    padding: 0 0.75rem;
}

/* Tabs */
.mode-tabs {
    display: flex;
    gap: 0.5rem;
    background: var(--bg-surface-2);
    padding: 4px;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.tab-btn {
    flex: 1;
    background: none;
    border: none;
    color: var(--text-muted);
    font-family: var(--font-body);
    font-size: 0.85rem;
    font-weight: 600;
    padding: 0.5rem;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: var(--transition);
}

.tab-btn.active {
    background: var(--bg-surface-3);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

/* Sliders */
.slider-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.slider-badge {
    font-family: var(--font-mono);
    font-size: 0.9rem;
    font-weight: 700;
    background: var(--bg-surface-3);
    border: 1px solid var(--border-color);
    color: var(--accent-hover);
    padding: 0.2rem 0.6rem;
    border-radius: var(--radius-sm);
}

.slider {
    appearance: none;
    width: 100%;
    height: 8px;
    background: var(--bg-surface-3);
    border-radius: 4px;
    outline: none;
    cursor: pointer;
}

.slider::-webkit-slider-thumb {
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--accent);
    border: 2px solid var(--text-primary);
    cursor: pointer;
    box-shadow: 0 0 10px var(--accent-glow-strong);
    transition: transform 0.1s ease;
}

.slider::-webkit-slider-thumb:hover {
    transform: scale(1.15);
}

.slider-ticks {
    display: flex;
    justify-content: space-between;
    font-size: 0.7rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
}

/* EMC Readout Box */
.emc-readout-box {
    background: var(--bg-surface-3);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.4rem;
    text-align: center;
}

.emc-label {
    font-size: 0.825rem;
    color: var(--text-secondary);
}

.emc-value {
    font-family: var(--font-mono);
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--wood-gold);
}

.emc-subtext {
    font-size: 0.725rem;
    color: var(--text-muted);
}

.btn-secondary {
    background: var(--bg-surface-2);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    font-family: var(--font-body);
    font-size: 0.85rem;
    font-weight: 600;
    padding: 0.4rem 0.9rem;
    border-radius: var(--radius-sm);
    cursor: pointer;
    margin-top: 0.4rem;
    transition: var(--transition);
}

.btn-secondary:hover {
    border-color: var(--accent);
    color: var(--accent-hover);
}

/* Advanced details */
.advanced-settings {
    border-top: 1px solid var(--border-color);
    padding-top: 0.75rem;
}

.advanced-settings summary {
    font-size: 0.85rem;
    color: var(--text-muted);
    cursor: pointer;
    font-weight: 600;
}

.advanced-settings summary:hover {
    color: var(--text-secondary);
}

.field-hint {
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* ── Results Side ── */
.status-pill {
    font-family: var(--font-body);
    font-size: 0.8rem;
    font-weight: 700;
    padding: 0.3rem 0.75rem;
    border-radius: 50px;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.status-contraction {
    background: rgba(56, 189, 248, 0.15);
    color: var(--status-contraction);
    border: 1px solid rgba(56, 189, 248, 0.3);
}

.status-expansion {
    background: rgba(245, 158, 11, 0.15);
    color: var(--status-expansion);
    border: 1px solid rgba(245, 158, 11, 0.3);
}

.status-stable {
    background: rgba(34, 197, 94, 0.15);
    color: var(--status-stable);
    border: 1px solid rgba(34, 197, 94, 0.3);
}

.results-hero-grid {
    display: grid;
    grid-template-columns: 1.2fr 1fr 1fr;
    gap: 0.85rem;
}

@media (max-width: 640px) {
    .results-hero-grid {
        grid-template-columns: 1fr;
    }
}

.result-box {
    background: var(--bg-surface-2);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.2rem;
}

.result-box.primary {
    border-color: var(--accent);
    background: linear-gradient(135deg, var(--bg-surface-2) 0%, var(--bg-surface-3) 100%);
    box-shadow: 0 4px 16px var(--accent-glow);
}

.result-label {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-weight: 600;
}

.result-value {
    font-family: var(--font-mono);
    font-size: 1.6rem;
    font-weight: 800;
    color: var(--text-primary);
}

.result-box.primary .result-value {
    color: var(--wood-gold);
}

.result-subtext {
    font-size: 0.775rem;
    color: var(--text-secondary);
    font-family: var(--font-mono);
}

/* Canvas Visualizer */
.visualizer-container {
    background: #0d0907;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.visualizer-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.visualizer-title {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--text-secondary);
}

.visualizer-hint {
    font-size: 0.725rem;
    color: var(--text-muted);
}

#woodCanvas {
    width: 100%;
    height: 220px;
    background: #090604;
    border-radius: var(--radius-sm);
    border: 1px solid #291c15;
}

.visualizer-legend {
    display: flex;
    justify-content: center;
    gap: 1.25rem;
    font-size: 0.75rem;
    color: var(--text-muted);
    flex-wrap: wrap;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.legend-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
}

.dot-original { background: #523b2b; }
.dot-shift { background: var(--accent); }
.dot-rings { background: var(--wood-gold); }

/* Joinery Advice */
.joinery-advice-box {
    border-top: 1px solid var(--border-color);
    padding-top: 1rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.joinery-advice-box h3 {
    font-family: var(--font-heading);
    font-size: 1.05rem;
    color: var(--text-primary);
}

.advice-grid {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.advice-card {
    background: var(--bg-surface-2);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 0.85rem 1rem;
    display: flex;
    gap: 0.85rem;
    align-items: flex-start;
}

.advice-icon {
    font-size: 1.3rem;
    background: var(--bg-surface-3);
    padding: 0.4rem;
    border-radius: var(--radius-sm);
    line-height: 1;
}

.advice-content h4 {
    font-size: 0.9rem;
    color: var(--text-primary);
    margin-bottom: 0.2rem;
}

.advice-content p {
    font-size: 0.825rem;
    color: var(--text-secondary);
    line-height: 1.4;
}

/* Seasonal Swing Card */
.swing-card {
    background: var(--bg-surface-2);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.6rem;
}

.swing-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.825rem;
    color: var(--text-secondary);
    font-weight: 600;
}

.swing-badge {
    font-family: var(--font-mono);
    color: var(--accent-hover);
    font-weight: 700;
}

.swing-bar-container {
    height: 10px;
    background: var(--bg-surface-3);
    border-radius: 5px;
    overflow: hidden;
}

.swing-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--wood-amber), var(--accent-hover));
    border-radius: 5px;
    transition: width 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.swing-note {
    font-size: 0.775rem;
    color: var(--text-muted);
}

/* ── Educational Section ── */
.educational-content {
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 2.5rem;
    margin-top: 2rem;
    display: flex;
    flex-direction: column;
    gap: 1.75rem;
}

.educational-content h2 {
    font-family: var(--font-heading);
    font-size: 1.6rem;
    color: var(--text-primary);
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
}

.educational-content p {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.content-grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.25rem;
}

@media (max-width: 840px) {
    .content-grid-3 {
        grid-template-columns: 1fr;
    }
}

.info-card {
    background: var(--bg-surface-2);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.25rem;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.info-card h3 {
    font-family: var(--font-heading);
    font-size: 1.1rem;
    color: var(--accent-hover);
}

.info-card ul {
    padding-left: 1.25rem;
    color: var(--text-secondary);
    font-size: 0.875rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

/* Data Table */
.table-responsive {
    overflow-x: auto;
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
    text-align: left;
}

.data-table th {
    background: var(--bg-surface-3);
    color: var(--text-primary);
    font-family: var(--font-heading);
    padding: 0.75rem 1rem;
    border-bottom: 2px solid var(--border-color);
}

.data-table td {
    padding: 0.75rem 1rem;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-secondary);
}

.data-table tr:hover td {
    background: var(--bg-surface-2);
}

.badge-stability {
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
    font-size: 0.775rem;
    font-weight: 600;
}

.badge-stability.stable {
    background: rgba(34, 197, 94, 0.15);
    color: #4ade80;
}

.badge-stability.moderate {
    background: rgba(245, 158, 11, 0.15);
    color: #fcd34d;
}

.badge-stability.active-move {
    background: rgba(239, 68, 68, 0.15);
    color: #fca5a5;
}

/* FAQ */
.faq-accordion {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.faq-item {
    background: var(--bg-surface-2);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
}

.faq-item summary {
    padding: 1rem 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    cursor: pointer;
    font-size: 0.95rem;
    transition: var(--transition);
}

.faq-item summary:hover {
    background: var(--bg-surface-3);
    color: var(--accent-hover);
}

.faq-answer {
    padding: 0 1.25rem 1rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
}