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

:root {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-card: #1e293b;
    --bg-input: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --accent-glow: rgba(59, 130, 246, 0.3);
    --border: #334155;
    --border-light: #475569;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --radius: 10px;
    --radius-sm: 6px;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
}

.msi-container {
    max-width: 1600px;
    margin: 0 auto;
    padding: 16px;
}

/* Header */
.msi-header {
    text-align: center;
    padding: 32px 24px;
    background: linear-gradient(135deg, #1e3a5f 0%, #0f172a 50%, #1a1a3e 100%);
    border-radius: var(--radius);
    border: 1px solid var(--border);
    margin-bottom: 20px;
    position: relative;
    overflow: hidden;
}

.msi-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--accent), #8b5cf6, #ec4899, var(--accent));
    background-size: 200% 100%;
    animation: gradientShift 4s linear infinite;
}

@keyframes gradientShift {
    0% { background-position: 0% 0%; }
    100% { background-position: 200% 0%; }
}

.msi-header h1 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 8px;
    background: linear-gradient(135deg, #60a5fa, #a78bfa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.msi-header .subtitle {
    font-size: 1rem;
    color: var(--text-secondary);
    max-width: 700px;
    margin: 0 auto;
}

/* Layout */
.msi-layout {
    display: grid;
    grid-template-columns: 280px 1fr;
    gap: 20px;
    margin-bottom: 24px;
}

/* Controls Sidebar */
.msi-controls {
    background: var(--bg-secondary);
    border-radius: var(--radius);
    border: 1px solid var(--border);
    padding: 20px;
    height: fit-content;
    position: sticky;
    top: 16px;
}

.msi-controls h3 {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--accent);
    margin-bottom: 16px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--border);
}

.control-group {
    background: var(--bg-primary);
    border-radius: var(--radius-sm);
    padding: 14px;
    margin-bottom: 14px;
    border: 1px solid var(--border);
}

.control-group h4 {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--accent);
    margin-bottom: 10px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.control-group label {
    display: block;
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: 4px;
    margin-top: 10px;
}

.control-group label:first-of-type {
    margin-top: 0;
}

.control-group label span:last-child,
.speed-label span:last-child {
    color: var(--success);
    font-weight: 700;
}

/* Sliders */
input[type="range"] {
    width: 100%;
    height: 6px;
    border-radius: 3px;
    background: var(--bg-input);
    outline: none;
    -webkit-appearance: none;
    appearance: none;
    cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--accent);
    cursor: pointer;
    box-shadow: 0 0 6px var(--accent-glow);
    transition: transform 0.15s ease;
}

input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

input[type="range"]::-moz-range-thumb {
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--accent);
    cursor: pointer;
    border: none;
    box-shadow: 0 0 6px var(--accent-glow);
}

/* Toggle Buttons */
.toggle-group {
    display: flex;
    gap: 6px;
}

.toggle-btn {
    flex: 1;
    padding: 8px 10px;
    font-size: 0.78rem;
    font-weight: 600;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background: var(--bg-input);
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.2s ease;
}

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

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

.color-toggles {
    flex-wrap: wrap;
}

/* Animation Controls */
.anim-controls {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.anim-btn {
    padding: 10px 16px;
    font-size: 0.85rem;
    font-weight: 700;
    border: none;
    border-radius: var(--radius-sm);
    background: linear-gradient(135deg, var(--accent), #8b5cf6);
    color: white;
    cursor: pointer;
    transition: all 0.2s ease;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.anim-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px var(--accent-glow);
}

.anim-btn.playing {
    background: linear-gradient(135deg, var(--danger), #dc2626);
}

.speed-label {
    font-size: 0.8rem;
    color: var(--text-secondary);
}

/* Preset Buttons */
.preset-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 6px;
}

.preset-btn {
    padding: 8px 6px;
    font-size: 0.72rem;
    font-weight: 600;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background: var(--bg-input);
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.2s ease;
}

.preset-btn:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: rgba(59, 130, 246, 0.1);
}

/* Visualization Area */
.msi-visualization {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

/* Stats Panel */
.stats-panel {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
}

.stat-item {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 12px 14px;
    text-align: center;
}

.stat-label {
    display: block;
    font-size: 0.72rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 4px;
}

.stat-value {
    display: block;
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--success);
    font-variant-numeric: tabular-nums;
}

/* Canvas Containers */
.canvas-container {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px;
}

.canvas-container h3 {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 12px;
}

.main-canvas-container canvas {
    width: 100%;
    height: auto;
    aspect-ratio: 1 / 1;
    border-radius: var(--radius-sm);
    background: #000;
    display: block;
}

.cross-section-container canvas {
    width: 100%;
    height: 180px;
    border-radius: var(--radius-sm);
    background: var(--bg-primary);
    display: block;
}

/* Education Section */
.msi-education {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px;
}

.msi-education h2 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 20px;
    background: linear-gradient(135deg, #60a5fa, #a78bfa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.edu-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
    margin-bottom: 24px;
}

.edu-card {
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 18px;
}

.edu-card h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--accent);
    margin-bottom: 10px;
}

.edu-card p {
    font-size: 0.88rem;
    color: var(--text-secondary);
    line-height: 1.75;
}

/* Formulas */
.formulas-section {
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 20px;
}

.formulas-section h3 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--accent);
    margin-bottom: 14px;
}

.formula-list {
    display: grid;
    gap: 10px;
}

.formula-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 14px;
    background: var(--bg-secondary);
    border-radius: var(--radius-sm);
    border: 1px solid var(--border);
}

.formula-label {
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--text-secondary);
    min-width: 150px;
    flex-shrink: 0;
}

.formula {
    font-family: 'Cambria Math', 'Times New Roman', serif;
    font-size: 0.95rem;
    color: var(--success);
    font-style: italic;
    letter-spacing: 0.3px;
}

/* Responsive: Tablet */
@media (max-width: 1024px) {
    .msi-layout {
        grid-template-columns: 1fr;
    }

    .msi-controls {
        position: static;
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
        gap: 12px;
    }

    .msi-controls h3 {
        grid-column: 1 / -1;
    }

    .control-group {
        margin-bottom: 0;
    }

    .edu-grid {
        grid-template-columns: 1fr;
    }

    .stats-panel {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* Responsive: Mobile */
@media (max-width: 640px) {
    .msi-container {
        padding: 8px;
    }

    .msi-header {
        padding: 20px 16px;
    }

    .msi-header h1 {
        font-size: 1.4rem;
    }

    .msi-header .subtitle {
        font-size: 0.85rem;
    }

    .msi-controls {
        grid-template-columns: 1fr;
        padding: 14px;
    }

    .msi-education {
        padding: 16px;
    }

    .stats-panel {
        grid-template-columns: 1fr 1fr;
        gap: 8px;
    }

    .stat-item {
        padding: 8px 10px;
    }

    .stat-label {
        font-size: 0.65rem;
    }

    .stat-value {
        font-size: 0.9rem;
    }

    .formula-item {
        flex-direction: column;
        align-items: flex-start;
    }

    .formula-label {
        min-width: auto;
    }

    .cross-section-container canvas {
        height: 140px;
    }

    .preset-grid {
        grid-template-columns: 1fr;
    }
}