:root {
    --primary: #6366f1;
    --primary-light: #818cf8;
    --bg-dark: #0f172a;
    --panel-bg: rgba(30, 41, 59, 0.85);
    --text-main: #f8fafc;
    --text-dim: #94a3b8;
    --accent: #f59e0b;
    --glass: rgba(255, 255, 255, 0.05);
    --glass-border: rgba(255, 255, 255, 0.1);
}

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

body {
    font-family: 'Outfit', sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-main);
    overflow: hidden;
    height: 100vh;
    width: 100vw;
}

#app {
    display: flex;
    height: 100vh;
    width: 100vw;
}

#ui-container {
    position: absolute;
    top: 20px;
    left: 20px;
    z-index: 10;
    width: 350px;
    pointer-events: none;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

#ui-container>* {
    pointer-events: auto;
}

header h1 {
    font-size: 1.8rem;
    font-weight: 600;
    background: linear-gradient(135deg, #fff 0%, var(--primary-light) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 4px;
}

header p {
    color: var(--text-dim);
    font-size: 0.9rem;
}

#topic-selector {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 8px;
    background: var(--panel-bg);
    padding: 12px;
    border-radius: 16px;
    backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

.topic-btn {
    background: var(--glass);
    border: 1px solid var(--glass-border);
    color: var(--text-main);
    padding: 10px;
    border-radius: 8px;
    cursor: pointer;
    font-family: inherit;
    font-size: 0.85rem;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    text-align: center;
}

.topic-btn:hover {
    background: var(--primary);
    transform: translateY(-2px);
}

.topic-btn.active {
    background: var(--primary);
    border-color: var(--primary-light);
    box-shadow: 0 0 15px rgba(99, 102, 241, 0.4);
}

#info-panel {
    background: var(--panel-bg);
    padding: 24px;
    border-radius: 20px;
    backdrop-filter: blur(16px);
    border: 1px solid var(--glass-border);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
}

#info-panel h2 {
    font-size: 1.2rem;
    margin-bottom: 12px;
    color: var(--accent);
}

#description {
    font-size: 0.95rem;
    line-height: 1.6;
    color: #cbd5e1;
    margin-bottom: 15px;
}

#math-display {
    background: rgba(0, 0, 0, 0.2);
    padding: 12px;
    border-radius: 8px;
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.9rem;
    border-left: 3px solid var(--primary);
}

#canvas-container {
    flex-grow: 1;
    height: 100%;
    width: 100%;
}

/* GUI Overwrites */
.lil-gui {
    --background-color: var(--panel-bg);
    --header-color: var(--bg-dark);
    --title-color: var(--text-main);
    --widget-color: rgba(255, 255, 255, 0.1);
    --hover-color: var(--primary);
    --focus-color: var(--primary);
    --number-color: var(--accent);
    --string-color: #10b981;
    --font-family: 'Outfit', sans-serif;
    border-radius: 12px;
    backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
}