:root {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent-primary: #38bdf8;
    --accent-secondary: #818cf8;
    --success: #4ade80;
    --warning: #fbbf24;
    --danger: #f87171;
    --border: #334155;
    --radius: 12px;
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.5;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    max-width: 1000px;
    /* Reduced max-width for vertical layout readability */
    margin: 0 auto;
    padding: 2rem;
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

header {
    text-align: center;
    /* margin-bottom handled by container gap */
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(to right, var(--accent-primary), var(--accent-secondary));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0.5rem;
}

header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* Dashboard Grid Layout (Controls + Charts) */
.dashboard {
    display: grid;
    gap: 1.5rem;
    grid-template-columns: 1fr;
}

@media (min-width: 1024px) {
    .dashboard {
        grid-template-columns: 350px 1fr;
        /* Fixed width controls, flexible charts */
        grid-template-areas: "controls charts";
        align-items: start;
    }

    .controls-panel {
        grid-area: controls;
    }

    .charts-panel {
        grid-area: charts;
    }
}

/* Panels Common Styles */
.visual-panel,
.controls-panel,
.charts-panel,
.theory-panel {
    background-color: var(--bg-secondary);
    border-radius: var(--radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
}

/* Visual Panel */
.diagram-container {
    background-color: #ffffff;
    border-radius: 8px;
    padding: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    height: 250px;
    /* Fixed height */
}

.diagram-container svg {
    max-height: 100%;
    max-width: 100%;
}

/* Theory Panel */
.theory-panel {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.theory-panel h2 {
    font-size: 1.25rem;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    border-bottom: 1px solid var(--border);
    padding-bottom: 0.5rem;
}

.theory-content {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1rem;
}

.theory-block h3 {
    font-size: 1rem;
    color: var(--accent-secondary);
    margin-bottom: 0.25rem;
}

.theory-block ul {
    list-style: none;
    padding: 0;
}

.theory-block li {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 0.25rem;
}

.theory-block li strong {
    color: var(--text-primary);
}

.theory-block p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 0.25rem;
}

.math {
    font-family: 'Times New Roman', serif;
    font-style: italic;
    color: var(--accent-primary);
    font-size: 1.1rem;
}

.theory-footer {
    margin-top: auto;
    padding: 0.75rem;
    background-color: var(--bg-tertiary);
    border-radius: 6px;
    font-size: 0.9rem;
    color: var(--text-secondary);
    border-left: 4px solid var(--success);
}

.theory-footer strong {
    color: var(--success);
}

/* Controls Panel */
.controls-panel {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.control-group label {
    font-weight: 500;
    color: var(--text-primary);
    display: flex;
    justify-content: space-between;
    font-size: 0.95rem;
}

.slider-wrapper {
    display: flex;
    align-items: center;
    gap: 1rem;
}

input[type="range"] {
    flex: 1;
    height: 6px;
    background: var(--bg-tertiary);
    border-radius: 3px;
    appearance: none;
    cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
    appearance: none;
    width: 18px;
    height: 18px;
    background: var(--accent-primary);
    border-radius: 50%;
    cursor: pointer;
    transition: transform 0.1s, background-color 0.2s;
}

input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.1);
    background-color: var(--accent-secondary);
}

.slider-value {
    font-family: 'Fira Code', monospace;
    min-width: 3.5rem;
    text-align: right;
    color: var(--accent-primary);
    font-weight: 600;
    font-size: 0.9rem;
}

/* Stats Panel (Inside Controls) */
.stats-panel {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.75rem;
}

.stat-card {
    background-color: var(--bg-tertiary);
    padding: 0.75rem;
    border-radius: 8px;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

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

.stat-value {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.stat-value.highlight {
    color: var(--accent-primary);
}

/* Charts Panel */
.charts-panel {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.equation-container {
    padding: 1rem;
    background: var(--bg-tertiary);
    border-radius: 8px;
    border-left: 4px solid var(--accent-primary);
}

.equation-container h3 {
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

#math-equation {
    font-family: 'Times New Roman', serif;
    font-style: italic;
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

#math-solution {
    font-family: 'Times New Roman', serif;
    font-size: 1.1rem;
    color: var(--accent-secondary);
}

.chart-container {
    position: relative;
    width: 100%;
    height: 300px;
    /* Taller charts */
    background: var(--bg-primary);
    border-radius: 8px;
    border: 1px solid var(--border);
    padding: 10px;
}

.chart-container h3 {
    position: absolute;
    top: 10px;
    left: 10px;
    margin: 0;
    font-size: 0.9rem;
    color: var(--text-secondary);
    background: var(--bg-primary);
    padding: 2px 6px;
    border-radius: 4px;
    z-index: 10;
}

canvas {
    width: 100%;
    height: 100%;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }

    header h1 {
        font-size: 1.75rem;
    }
}