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

:root {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --accent-blue: #3b82f6;
    --accent-green: #22c55e;
    --accent-orange: #f97316;
    --accent-red: #ef4444;
    --border-color: #475569;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, var(--bg-primary) 0%, #1a1a2e 100%);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
}

.plate-tectonics-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px;
}

header {
    text-align: center;
    padding: 30px 20px;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 30px;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, #60a5fa, #f97316);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 10px;
}

.subtitle {
    font-size: 1.1rem;
    color: var(--text-secondary);
    max-width: 700px;
    margin: 0 auto;
}

.simulation-layout {
    display: grid;
    grid-template-columns: 1fr 380px;
    gap: 25px;
    margin-bottom: 40px;
}

@media (max-width: 1100px) {
    .simulation-layout {
        grid-template-columns: 1fr;
    }
}

.canvas-panel {
    background: var(--bg-secondary);
    border-radius: 16px;
    padding: 20px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.boundary-selector {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.boundary-btn {
    flex: 1;
    min-width: 150px;
    padding: 12px 20px;
    background: var(--bg-tertiary);
    border: 2px solid var(--border-color);
    border-radius: 10px;
    color: var(--text-primary);
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.boundary-btn:hover {
    background: var(--bg-secondary);
    border-color: var(--accent-blue);
    transform: translateY(-2px);
}

.boundary-btn.active {
    background: linear-gradient(135deg, var(--accent-blue), #2563eb);
    border-color: var(--accent-blue);
    box-shadow: 0 4px 15px rgba(59, 130, 246, 0.4);
}

.canvas-container {
    position: relative;
    background: linear-gradient(180deg, #0a1628 0%, #1a365d 100%);
    border-radius: 12px;
    overflow: hidden;
    margin-bottom: 20px;
    box-shadow: inset 0 2px 10px rgba(0, 0, 0, 0.5);
}

#tectonicsCanvas {
    display: block;
    width: 100%;
    height: auto;
}

.phenomenon-info {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 15px;
    margin-bottom: 20px;
}

.info-item {
    background: var(--bg-tertiary);
    padding: 12px 16px;
    border-radius: 10px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.info-item span:first-child {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.info-item span:last-child {
    color: var(--accent-orange);
    font-weight: 700;
    font-size: 1.1rem;
}

.legend-section {
    background: var(--bg-tertiary);
    padding: 16px;
    border-radius: 10px;
}

.legend-section h4 {
    margin-bottom: 12px;
    color: var(--text-secondary);
    font-size: 0.95rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.legend-items {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 10px;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
}

.legend-color {
    width: 20px;
    height: 20px;
    border-radius: 4px;
    flex-shrink: 0;
}

.legend-color.crust {
    background: linear-gradient(135deg, #4a90d9, #5cb85c);
}

.legend-color.mantle {
    background: linear-gradient(135deg, #ff6b35, #ffa62b);
}

.legend-color.magma {
    background: radial-gradient(circle, #ff4500, #ff6b35);
}

.legend-color.plate-a {
    background: #4a90d9;
}

.legend-color.plate-b {
    background: #5cb85c;
}

.controls-panel {
    background: var(--bg-secondary);
    border-radius: 16px;
    padding: 20px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
    max-height: fit-content;
}

.controls-panel h3 {
    font-size: 1.3rem;
    margin-bottom: 20px;
    color: var(--accent-blue);
}

.control-group {
    margin-bottom: 25px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border-color);
}

.control-group:last-child {
    border-bottom: none;
}

.control-group h4 {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin-bottom: 12px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.control-group label {
    display: block;
    margin-bottom: 8px;
    color: var(--text-primary);
    font-size: 0.95rem;
}

.control-group label span {
    color: var(--accent-orange);
    font-weight: 600;
}

.control-group input[type="range"] {
    width: 100%;
    height: 8px;
    background: var(--bg-tertiary);
    border-radius: 4px;
    outline: none;
    margin-bottom: 15px;
    -webkit-appearance: none;
}

.control-group input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 18px;
    height: 18px;
    background: var(--accent-blue);
    border-radius: 50%;
    cursor: pointer;
    transition: all 0.2s ease;
}

.control-group input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
    box-shadow: 0 0 10px rgba(59, 130, 246, 0.5);
}

.control-group input[type="range"]::-moz-range-thumb {
    width: 18px;
    height: 18px;
    background: var(--accent-blue);
    border-radius: 50%;
    cursor: pointer;
    border: none;
}

.control-group select {
    width: 100%;
    padding: 10px 15px;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 0.95rem;
    cursor: pointer;
    outline: none;
}

.control-group select:focus {
    border-color: var(--accent-blue);
}

.checkbox-input {
    width: auto !important;
    margin-right: 10px;
    accent-color: var(--accent-blue);
}

.checkbox-input + span,
.control-group label:has(.checkbox-input) {
    display: flex;
    align-items: center;
    cursor: pointer;
}

.button-group {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

.control-button {
    flex: 1;
    padding: 12px 20px;
    border: none;
    border-radius: 10px;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.control-button.start {
    background: linear-gradient(135deg, #22c55e, #16a34a);
    color: white;
}

.control-button.start:hover {
    box-shadow: 0 4px 15px rgba(34, 197, 94, 0.4);
    transform: translateY(-2px);
}

.control-button.pause {
    background: linear-gradient(135deg, #f59e0b, #d97706);
    color: white;
}

.control-button.pause:hover {
    box-shadow: 0 4px 15px rgba(245, 158, 11, 0.4);
    transform: translateY(-2px);
}

.control-button.reset {
    background: linear-gradient(135deg, #ef4444, #dc2626);
    color: white;
}

.control-button.reset:hover {
    box-shadow: 0 4px 15px rgba(239, 68, 68, 0.4);
    transform: translateY(-2px);
}

.formulas-section {
    background: var(--bg-tertiary);
    padding: 16px;
    border-radius: 10px;
}

.formulas-section h3 {
    font-size: 1rem;
    margin-bottom: 15px;
    color: var(--accent-orange);
}

.formula-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.formula-item {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.formula-label {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.formula {
    font-size: 0.9rem;
    color: var(--text-primary);
    background: var(--bg-secondary);
    padding: 8px 12px;
    border-radius: 6px;
    border-left: 3px solid var(--accent-blue);
}

.explanation {
    background: var(--bg-secondary);
    border-radius: 16px;
    padding: 30px;
    margin-top: 30px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
}

.explanation h2 {
    font-size: 1.8rem;
    margin-bottom: 20px;
    color: var(--accent-blue);
}

.explanation h3 {
    font-size: 1.4rem;
    margin-top: 30px;
    margin-bottom: 15px;
    color: var(--accent-orange);
}

.explanation p {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 15px;
}

.explanation strong {
    color: var(--text-primary);
}

@media (max-width: 768px) {
    header h1 {
        font-size: 1.8rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    .boundary-selector {
        flex-direction: column;
    }

    .button-group {
        flex-direction: column;
    }

    .phenomenon-info {
        grid-template-columns: 1fr;
    }
}

/* Animation for visual feedback */
@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.6;
    }
}

.running .info-item span:last-child {
    animation: pulse 1s ease-in-out infinite;
}