:root {
    --bg-deep: #030510;
    --bg-gradient-top: #040714;
    --bg-gradient-bottom: #080c1f;
    --panel-bg: rgba(8, 12, 30, 0.68);
    --panel-border: rgba(255, 255, 255, 0.08);
    --accent: #ffa54c;
    --accent-soft: #5cd2ff;
    --text-main: #f0f4ff;
    --text-muted: rgba(240, 244, 255, 0.72);
    --font-sans: "Source Han Sans", "Noto Sans SC", "Helvetica Neue", Arial, sans-serif;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100vh;
    font-family: var(--font-sans);
    color: var(--text-main);
    background: linear-gradient(160deg, var(--bg-gradient-top), var(--bg-gradient-bottom));
    overflow: hidden;
}

#scene-canvas {
    position: fixed;
    inset: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
    display: block;
}


.ui-layer {
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    width: clamp(260px, 25vw, 360px);
    z-index: 1;
    padding: clamp(18px, 3vw, 28px);
    display: flex;
    flex-direction: column;
    gap: 16px;
    pointer-events: auto;
    overflow-y: auto;
    transition: transform 0.3s cubic-bezier(0.4, 0.0, 0.2, 1);
}

.ui-layer::after {
    content: "";
    position: absolute;
    top: 0;
    right: -80px;
    bottom: 0;
    width: 160px;
    background: linear-gradient(90deg, rgba(5,8,20,0.45), rgba(5,8,20,0));
    pointer-events: none;
}

.ui-layer > * {
    position: relative;
    z-index: 1;
}

.ui-column {
    display: flex;
    flex-direction: column;
    gap: 16px;
    width: 100%;
}

.panel {
    background: var(--panel-bg);
    border: 1px solid var(--panel-border);
    border-radius: 18px;
    padding: clamp(18px, 3vw, 34px);
    backdrop-filter: blur(14px);
    box-shadow: 0 30px 80px rgba(0, 0, 0, 0.45);
    pointer-events: auto;
}

.hero h1 {
    margin: 6px 0 12px;
    font-size: clamp(1.6rem, 3vw, 2.4rem);
}

.eyebrow {
    text-transform: uppercase;
    letter-spacing: 0.35em;
    font-size: 0.75rem;
    color: var(--text-muted);
}

.intro {
    margin-top: 8px;
    line-height: 1.7;
    color: var(--text-muted);
}

.stage-info {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.info-header {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 10px;
}

.tag {
    padding: 4px 10px;
    border-radius: 999px;
    border: 1px solid rgba(255, 255, 255, 0.2);
    font-size: 0.8rem;
    color: var(--accent-soft);
}

#stage-description {
    margin: 0;
    line-height: 1.8;
    color: var(--text-muted);
}

.facts-list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 14px;
}

.facts-list li {
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: 12px;
    padding: 12px;
    font-size: 0.9rem;
    line-height: 1.4;
}

.facts-list strong {
    display: block;
    font-size: 0.75rem;
    letter-spacing: 0.2em;
    color: var(--accent-soft);
    text-transform: uppercase;
    margin-bottom: 4px;
}

.stage-controls {
    display: flex;
    flex-direction: column;
    gap: 18px;
}

.controls-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

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

.stage-chip {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: 12px;
    padding: 12px 10px;
    color: var(--text-main);
    font-size: 0.9rem;
    cursor: pointer;
    transition: border 0.2s, transform 0.2s, background 0.2s;
}

.stage-chip.active {
    border-color: var(--accent);
    background: rgba(255, 165, 76, 0.12);
    color: var(--accent);
    box-shadow: 0 10px 30px rgba(255, 165, 76, 0.25);
}

.stage-chip:hover {
    transform: translateY(-2px);
}

.control-row {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

button {
    font-family: inherit;
    border: none;
    border-radius: 999px;
    padding: 10px 20px;
    cursor: pointer;
    background: var(--accent);
    color: #1a0d05;
    font-weight: 600;
    transition: opacity 0.2s, transform 0.2s;
}

button:hover {
    opacity: 0.9;
    transform: translateY(-1px);
}

button.ghost {
    background: transparent;
    border: 1px solid rgba(255, 255, 255, 0.25);
    color: var(--text-main);
}

.footnote {
    margin: 0;
    font-size: 0.8rem;
    color: var(--text-muted);
}

.control-dock {
    position: absolute;
    z-index: 1;
    bottom: clamp(20px, 4vh, 40px);
    left: calc(clamp(260px, 25vw, 360px) + clamp(16px, 2.5vw, 36px));
    right: clamp(16px, 4vw, 56px);
    pointer-events: auto;
}

.dock-toggle {
    position: absolute;
    top: -36px;
    right: clamp(16px, 2vw, 30px);
    padding: 8px 16px;
    border-radius: 999px;
    border: 1px solid rgba(255,255,255,0.25);
    background: rgba(8,12,30,0.7);
    color: var(--text-main);
    font-family: var(--font-sans);
    cursor: pointer;
    pointer-events: auto;
    backdrop-filter: blur(8px);
    transition: transform 0.2s, opacity 0.2s, border-color 0.2s;
}

.dock-toggle:hover {
    transform: translateY(-1px);
}

.control-dock .panel {
    pointer-events: auto;
    transition: transform 0.35s ease, opacity 0.35s ease;
}

.control-dock.collapsed .panel {
    transform: translateY(140%);
    opacity: 0;
    pointer-events: none;
}

/* Sidebar Toggle for Mobile */
.sidebar-toggle {
    display: none;
    position: absolute;
    top: 20px;
    right: 20px;
    width: 30px;
    height: 30px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    z-index: 20;
}

.sidebar-toggle::after {
    content: '';
    display: block;
    width: 10px;
    height: 10px;
    border-right: 2px solid white;
    border-bottom: 2px solid white;
    transform: rotate(45deg);
    margin-top: -4px;
    transition: transform 0.3s;
}

.ui-layer.collapsed .sidebar-toggle::after {
    transform: rotate(-135deg);
    margin-top: 4px;
}


@media (max-width: 1200px) {
    .ui-layer {
        width: clamp(260px, 34vw, 420px);
    }

    .control-dock {
        left: clamp(260px, 34vw, 420px);
    }
}

@media (max-width: 980px) {
    body {
        overflow: hidden; /* Keep hidden to avoid scroll on mobile */
    }

    .ui-layer {
        position: absolute;
        top: 0;
        left: 0;
        right: 0;
        width: 100%;
        max-width: none;
        padding: 16px;
        background: rgba(0,0,0,0.85);
        backdrop-filter: blur(20px);
        height: 100vh;
        transform: translateY(0);
        z-index: 200; /* Highest */
    }

    .ui-layer.collapsed {
        transform: translateY(-100%);
    }

    /* When collapsed, show a small header or toggle button? */
    /* Actually, if we collapse it up, we need a button to bring it back. */
    /* The button is inside .ui-layer, so it moves with it. */
    /* We need the toggle button to be fixed on screen or stick out. */
    
    .sidebar-toggle {
        display: flex;
        position: fixed;
        top: 20px;
        left: 20px;
        right: auto;
        z-index: 201;
    }
    
    /* Move toggle down when collapsed so it's visible? */
    /* Or keep it fixed at top-left. */

    .ui-layer::after {
        display: none;
    }

    .control-dock {
        position: fixed;
        left: 0;
        right: 0;
        bottom: 0;
        margin: 0;
        pointer-events: auto;
        z-index: 100;
    }
    
    .control-dock .panel {
        border-radius: 20px 20px 0 0;
        border-bottom: none;
    }
}

@media (max-width: 640px) {
    .timeline {
        grid-template-columns: repeat(auto-fit, minmax(110px, 1fr));
    }

    .control-row {
        flex-direction: column;
    }
}

.back-to-home {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 8px 16px;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 999px;
    color: var(--text-main);
    text-decoration: none;
    font-size: 0.9rem;
    backdrop-filter: blur(10px);
    transition: background 0.2s;
    z-index: 300;
}

.back-to-home:hover {
    background: rgba(255, 255, 255, 0.2);
}