/* ===== CSS Variables & Reset ===== */
:root {
    --bg-primary: #f0f4f8;
    --bg-secondary: #ffffff;
    --bg-tertiary: #e8eef4;
    --text-primary: #1a1a2e;
    --text-secondary: #5a6270;
    --border-color: #d0d8e0;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);

    /* Chromatography Colors */
    --paper-color: #faf8f5;
    --paper-border: #e0dcd5;
    --solvent-color: rgba(200, 220, 240, 0.6);
    --accent-color: #9b59b6;

    --radius: 12px;
    --transition: all 0.3s ease;
}

[data-theme="dark"] {
    --bg-primary: #0f0f1a;
    --bg-secondary: #1a1a2e;
    --bg-tertiary: #252540;
    --text-primary: #f0f4f8;
    --text-secondary: #a0a8b8;
    --border-color: #2a2a45;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
    --paper-color: #f5f3f0;
    --paper-border: #d5d0c8;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    transition: var(--transition);
}

/* ===== App Container ===== */
.app-container {
    max-width: 1800px;
    margin: 0 auto;
    padding: 15px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ===== Header ===== */
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 25px;
    background: var(--bg-secondary);
    border-radius: var(--radius);
    margin-bottom: 15px;
    box-shadow: var(--shadow);
}

.header h1 {
    font-size: 1.5rem;
    font-weight: 700;
    color: #9b59b6;
}

.header-controls {
    display: flex;
    gap: 10px;
}

.control-btn {
    width: 42px;
    height: 42px;
    border: 2px solid var(--border-color);
    border-radius: 50%;
    background: var(--bg-primary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.control-btn:hover {
    border-color: var(--accent-color);
    transform: scale(1.05);
}

.control-btn svg {
    width: 20px;
    height: 20px;
    color: var(--text-primary);
}

.moon-icon {
    display: none;
}

[data-theme="dark"] .sun-icon {
    display: none;
}

[data-theme="dark"] .moon-icon {
    display: block;
}

.compress-icon {
    display: none;
}

.fullscreen-active .expand-icon {
    display: none;
}

.fullscreen-active .compress-icon {
    display: block;
}

/* ===== Main Content ===== */
.main-content {
    display: grid;
    grid-template-columns: 240px 1fr 280px;
    gap: 15px;
    flex: 1;
}

/* ===== Controls Panel ===== */
.controls-panel {
    background: var(--bg-secondary);
    border-radius: var(--radius);
    padding: 20px;
    box-shadow: var(--shadow);
    display: flex;
    flex-direction: column;
    gap: 18px;
}

.controls-panel h2 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
}

.control-section h3 {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 10px;
    text-transform: uppercase;
}

/* Sample Grid */
.sample-grid {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.sample-btn {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 12px;
    background: var(--bg-tertiary);
    border: 2px solid transparent;
    border-radius: 8px;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-primary);
    cursor: pointer;
    transition: var(--transition);
    text-align: left;
}

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

.sample-btn.active {
    background: var(--accent-color);
    color: white;
    border-color: var(--accent-color);
}

.sample-dot {
    width: 16px;
    height: 16px;
    border-radius: 50%;
    border: 2px solid rgba(0, 0, 0, 0.2);
    flex-shrink: 0;
}

/* Solvent Buttons */
.solvent-buttons {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.solvent-btn {
    padding: 10px;
    background: var(--bg-tertiary);
    border: 2px solid transparent;
    border-radius: 8px;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-primary);
    cursor: pointer;
    transition: var(--transition);
    text-align: left;
}

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

.solvent-btn.active {
    background: var(--text-primary);
    color: var(--bg-primary);
    border-color: var(--text-primary);
}

/* Playback Buttons */
.playback-buttons {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.playback-btn {
    padding: 12px;
    background: var(--bg-tertiary);
    border: 2px solid transparent;
    border-radius: 10px;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-primary);
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

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

.playback-btn.primary {
    background: linear-gradient(135deg, #9b59b6, #8e44ad);
    color: white;
}

.playback-btn.primary:hover {
    transform: scale(1.02);
}

.playback-btn.primary.playing {
    background: linear-gradient(135deg, #e74c3c, #c0392b);
}

.pause-icon {
    display: none;
}

.playback-btn.primary.playing .play-icon {
    display: none;
}

.playback-btn.primary.playing .pause-icon {
    display: inline;
}

.playback-btn.primary.playing .btn-text::after {
    content: 'Pauza';
}

.playback-btn.primary.playing .btn-text {
    font-size: 0;
}

/* Speed Buttons */
.speed-buttons {
    display: flex;
    gap: 6px;
}

.speed-btn {
    flex: 1;
    padding: 10px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    background: var(--bg-tertiary);
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
}

.speed-btn.active {
    background: var(--text-primary);
    color: var(--bg-primary);
    border-color: var(--text-primary);
}

/* Time Display */
.time-section {
    background: var(--bg-tertiary);
    border-radius: 10px;
    padding: 15px;
    margin-top: auto;
}

.time-display {
    text-align: center;
    margin-top: 8px;
}

#timeValue {
    font-size: 2rem;
    font-weight: 800;
    color: var(--accent-color);
}

.time-unit {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-left: 5px;
}

/* ===== Simulation Container ===== */
.simulation-container {
    background: var(--bg-secondary);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.simulation-header {
    text-align: center;
    padding: 10px 15px;
    background: linear-gradient(135deg, rgba(155, 89, 182, 0.1), rgba(142, 68, 173, 0.1));
    border-radius: 10px;
    border-left: 4px solid #9b59b6;
}

.simulation-header h2 {
    font-size: 1.1rem;
    font-weight: 700;
    color: #9b59b6;
    margin-bottom: 6px;
}

.simulation-header p {
    font-size: 0.8rem;
    color: var(--text-secondary);
    line-height: 1.5;
    max-width: 600px;
    margin: 0 auto;
}

.simulation-wrapper {
    flex: 1;
    position: relative;
    background: linear-gradient(180deg, #f5f5f5 0%, #e8e8e8 100%);
    border-radius: 12px;
    overflow: hidden;
    min-height: 450px;
    border: 3px solid var(--border-color);
}

[data-theme="dark"] .simulation-wrapper {
    background: linear-gradient(180deg, #2a2a3e 0%, #1f1f30 100%);
}

#chromatographyCanvas {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
}

/* Scale Ruler */
.scale-ruler {
    position: absolute;
    left: 10px;
    top: 50px;
    bottom: 50px;
    width: 30px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    font-size: 0.65rem;
    color: var(--text-secondary);
}

/* Front Indicator */
.front-indicator {
    position: absolute;
    right: 20px;
    display: flex;
    align-items: center;
    gap: 8px;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.front-indicator.visible {
    opacity: 1;
}

.front-line {
    width: 30px;
    height: 2px;
    background: var(--accent-color);
}

.front-label {
    font-size: 0.7rem;
    color: var(--accent-color);
    font-weight: 600;
    white-space: nowrap;
}

/* Results Bar */
.results-bar {
    background: var(--bg-tertiary);
    border-radius: 10px;
    padding: 15px;
}

.results-bar h3 {
    font-size: 0.9rem;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.rf-values {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.rf-placeholder {
    font-size: 0.8rem;
    color: var(--text-secondary);
    font-style: italic;
}

.rf-item {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 12px;
    background: var(--bg-secondary);
    border-radius: 20px;
    font-size: 0.8rem;
}

.rf-dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
}

.rf-value {
    font-weight: 700;
    color: var(--text-primary);
}

.rf-name {
    color: var(--text-secondary);
}

/* ===== Info Panel ===== */
.info-panel {
    background: var(--bg-secondary);
    border-radius: var(--radius);
    padding: 20px;
    box-shadow: var(--shadow);
    display: flex;
    flex-direction: column;
    gap: 15px;
    overflow-y: auto;
}

.info-panel h2 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
}

.info-card {
    background: var(--bg-tertiary);
    border-radius: 10px;
    padding: 15px;
}

.info-card h3 {
    font-size: 0.9rem;
    margin-bottom: 8px;
}

.info-card p {
    font-size: 0.8rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

.info-card ul {
    list-style: none;
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.info-card ul li {
    padding: 4px 0;
    position: relative;
    padding-left: 15px;
}

.info-card ul li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--accent-color);
}

.info-card.highlight {
    background: linear-gradient(135deg, rgba(155, 89, 182, 0.15), rgba(142, 68, 173, 0.1));
    border-left: 4px solid var(--accent-color);
}

/* Formula Card */
.formula-card {
    background: var(--bg-tertiary);
    border-radius: 10px;
    padding: 15px;
}

.formula-card h3 {
    font-size: 0.9rem;
    margin-bottom: 12px;
}

.formula {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 15px 10px;
    background: var(--bg-secondary);
    border-radius: 8px;
    margin-bottom: 10px;
}

.formula-text {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--accent-color);
    flex-shrink: 0;
}

.fraction {
    display: flex;
    flex-direction: column;
    align-items: center;
    font-size: 0.75rem;
    line-height: 1.3;
    text-align: center;
}

.numerator {
    border-bottom: 2px solid var(--text-primary);
    padding: 0 8px 4px 8px;
    white-space: nowrap;
}

.denominator {
    padding: 4px 8px 0 8px;
    white-space: nowrap;
}

.formula-note {
    font-size: 0.75rem;
    color: var(--text-secondary);
    line-height: 1.4;
}

/* Legend Card */
.legend-card {
    background: var(--bg-tertiary);
    border-radius: 10px;
    padding: 15px;
}

.legend-card h3 {
    font-size: 0.9rem;
    margin-bottom: 10px;
}

.legend-items {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.legend-placeholder {
    font-size: 0.8rem;
    color: var(--text-secondary);
    font-style: italic;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.legend-dot {
    width: 16px;
    height: 16px;
    border-radius: 50%;
    border: 2px solid rgba(0, 0, 0, 0.15);
}

/* ===== Responsive ===== */
@media (max-width: 1200px) {
    .main-content {
        grid-template-columns: 200px 1fr 240px;
    }
}

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

    .controls-panel {
        order: 1;
    }

    .simulation-container {
        order: 2;
        min-height: 400px;
    }

    .info-panel {
        order: 3;
    }

    .sample-grid {
        display: grid;
        grid-template-columns: 1fr 1fr;
    }
}