:root {
    --bg-color: #000000;
    --particle-color: #ffffff;
    --text-color: #ffffff;
    --accent-color: #ffffff;
    --glass-bg: rgba(20, 20, 20, 0.6);
    --glass-border: rgba(255, 255, 255, 0.1);
    --font-family: 'Outfit', sans-serif;
}

/* Theme: Paper (Blau auf Papier) */
[data-theme="paper"] {
    --bg-color: #f4ecd8;
    --particle-color: #0044ff;
    --text-color: #1a1a1a;
    --accent-color: #0044ff;
    --glass-bg: rgba(255, 255, 255, 0.6);
    --glass-border: rgba(0, 0, 0, 0.1);
}

/* Theme: Neon Cyberpunk */
[data-theme="neon"] {
    --bg-color: #050510;
    --particle-color: #00ffcc;
    --text-color: #e0e0ff;
    --accent-color: #ff00ff;
    --glass-bg: rgba(10, 10, 20, 0.7);
    --glass-border: rgba(0, 255, 204, 0.2);
}

/* Theme: Sunset */
[data-theme="sunset"] {
    --bg-color: #2d1b2e;
    --particle-color: #ff9a8b;
    --text-color: #ffd1dc;
    --accent-color: #ff6b6b;
    --glass-bg: rgba(60, 30, 60, 0.5);
    --glass-border: rgba(255, 154, 139, 0.2);
}

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

body {
    font-family: var(--font-family);
    background-color: var(--bg-color);
    color: var(--text-color);
    overflow: hidden;
    /* Prevent scrollbars */
    transition: background-color 0.5s ease, color 0.5s ease;
    height: 100vh;
    width: 100vw;
}

canvas {
    display: block;
    position: absolute;
    top: 0;
    left: 0;
    z-index: 1;
}

/* Opening Sequence */
#opening-sequence {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 100;
    display: flex;
    justify-content: center;
    align-items: center;
}

.sequence-overlay {
    position: absolute;
    text-align: center;
    opacity: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

#title-overlay h1 {
    font-size: 5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    letter-spacing: -0.05em;
    text-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

#title-overlay p {
    font-size: 1.5rem;
    font-weight: 300;
    opacity: 0.8;
}

#instructions-overlay p {
    font-size: 1.5rem;
    font-weight: 300;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.key-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2rem;
    height: 2rem;
    border: 1px solid currentColor;
    border-radius: 6px;
    font-size: 1.2rem;
    font-weight: 500;
    background: rgba(255, 255, 255, 0.1);
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: scale(0.95);
    }

    to {
        opacity: 1;
        transform: scale(1);
    }
}

@keyframes fadeOut {
    from {
        opacity: 1;
        transform: scale(1);
    }

    to {
        opacity: 0;
        transform: scale(1.05);
    }
}

/* UI Layer */
.ui-layer {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 50;
}

.ui-layer>* {
    pointer-events: auto;
}

/* Top Panel (Slider) */
.top-panel {
    position: absolute;
    top: 2rem;
    left: 50%;
    transform: translateX(-50%);
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    padding: 1rem 2rem;
    border-radius: 50px;
    opacity: 0.3;
    transition: opacity 0.3s ease, transform 0.3s ease;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.top-panel:hover {
    opacity: 1;
}

.slider-container {
    display: flex;
    align-items: center;
    gap: 1rem;
    width: 300px;
}

#coherence-value {
    font-variant-numeric: tabular-nums;
    font-weight: 500;
    min-width: 3ch;
    text-align: right;
}

/* Bottom Panel (Colors) */
.bottom-panel {
    position: absolute;
    bottom: 2rem;
    left: 2rem;
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    padding: 0.75rem;
    border-radius: 16px;
    opacity: 0.3;
    transition: opacity 0.3s ease;
}

.bottom-panel:hover {
    opacity: 1;
}

/* Panel Hints */
.panel-hint {
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%);
    margin-top: 0.75rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.25rem;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.5s ease;
}

.panel-hint-bottom {
    top: auto;
    bottom: 100%;
    margin-top: 0;
    margin-bottom: 0.75rem;
    flex-direction: column-reverse;
}

.hint-text {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-color);
    white-space: nowrap;
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.5);
}

.hint-arrow {
    font-size: 1.5rem;
    color: var(--accent-color);
    animation: bounceArrow 1s ease-in-out infinite;
}

.panel-hint-bottom .hint-arrow {
    animation: bounceArrowDown 1s ease-in-out infinite;
}

@keyframes bounceArrow {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-6px); }
}

@keyframes bounceArrowDown {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(6px); }
}

/* Show hints during intro */
.show-hints .panel-hint {
    opacity: 1;
}

.show-hints .top-panel,
.show-hints .bottom-panel {
    opacity: 1;
}

.theme-buttons {
    display: flex;
    gap: 0.5rem;
}

.theme-btn {
    background: none;
    border: none;
    cursor: pointer;
    padding: 2px;
    border-radius: 50%;
    transition: transform 0.2s ease;
}

.theme-btn:hover {
    transform: scale(1.1);
}

.theme-btn.active {
    box-shadow: 0 0 0 2px var(--accent-color);
}

.color-preview {
    display: block;
    width: 24px;
    height: 24px;
    border-radius: 50%;
}

/* Slider Styling */
input[type="range"] {
    flex: 1;
    -webkit-appearance: none;
    appearance: none;
    background: transparent;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    height: 16px;
    width: 16px;
    border-radius: 50%;
    background: var(--accent-color);
    cursor: pointer;
    margin-top: -6px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.2);
    transition: transform 0.1s;
}

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

input[type="range"]::-webkit-slider-runnable-track {
    width: 100%;
    height: 4px;
    cursor: pointer;
    background: rgba(128, 128, 128, 0.3);
    border-radius: 2px;
}