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

:root {
    --bg: #0d0d0d;
    --stage: #1a1a1a;
    --line: #262626;
    --text: #d6d6d6;
    --muted: #8a8a8a;
    --heading: #f2f2f2;
    --accent: #00ff88;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    overflow: hidden;
    line-height: 1.6;
}

a {
    color: var(--accent);
}

.app-container {
    width: 100vw;
    height: 100vh;
    display: flex;
}

.sidebar {
    width: 190px;
    height: 100vh;
    overflow-y: auto;
    flex-shrink: 0;
}

.main-container {
    flex: 1;
    height: 100vh;
    overflow-y: auto;
    scrollbar-gutter: stable;
}

body:has(.lightbox[open]) .main-container {
    overflow: hidden;
}

/* Concept pages */

.page {
    max-width: 1280px;
    margin: 0 auto;
    padding: 24px 32px 40px;
}

.page h1 {
    color: var(--heading);
    font-size: 28px;
    line-height: 1.2;
}

.lede {
    color: var(--muted);
    font-size: 16px;
    margin: 6px 0 20px;
    max-width: 70ch;
}

.page h2 {
    color: var(--heading);
    font-size: 18px;
    margin: 28px 0 8px;
}

.page p,
.page ul,
.page ol {
    font-size: 15px;
    max-width: 70ch;
    margin-bottom: 12px;
}

.page ul,
.page ol {
    padding-left: 20px;
}

.page li {
    margin-bottom: 4px;
}

.page strong {
    color: var(--heading);
}

/* Brochure: a grid of panels, each a small 3D scene with a caption */

.spread {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 28px 20px;
    margin: 8px 0 12px;
}

.panel.wide {
    grid-column: span 2;
}

.view {
    position: relative;
    aspect-ratio: 4 / 3;
    background: var(--stage);
    border-radius: 6px;
    overflow: hidden;
}

.panel.wide .view {
    aspect-ratio: 2 / 1;
}

.view canvas,
.lightbox-stage canvas {
    display: block;
    width: 100%;
    height: 100%;
}

canvas.draggable {
    cursor: grab;
    touch-action: none;
}

canvas.draggable:active {
    cursor: grabbing;
}

.icon-btn {
    display: inline-grid;
    place-items: center;
    width: 32px;
    height: 32px;
    flex-shrink: 0;
    border: 0;
    border-radius: 6px;
    background: transparent;
    color: var(--text);
    cursor: pointer;
}

.icon-btn:hover {
    background: rgb(255 255 255 / 0.1);
    color: var(--heading);
}

.icon-btn:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 1px;
}

.icon-btn svg {
    width: 18px;
    height: 18px;
}

.view .expand {
    position: absolute;
    top: 8px;
    right: 8px;
    background: rgb(13 13 13 / 0.7);
    opacity: 0;
    transition: opacity 0.15s;
}

.view .expand:hover {
    background: rgb(40 40 40 / 0.9);
}

.panel:hover .expand,
.view .expand:focus-visible {
    opacity: 1;
}

@media (hover: none) {
    .view .expand {
        opacity: 1;
    }
}

/* Expanded panel: a modal with the scene at full size */

.lightbox {
    --aspect: 4 / 3;
    --fit: min(94vw, (100dvh - 180px) * var(--aspect));
    width: var(--fit);
    max-width: none;
    max-height: none;
    margin: auto;
    padding: 0;
    border: 1px solid var(--line);
    border-radius: 8px;
    background: var(--bg);
    color: var(--text);
    overflow: hidden;
}

.lightbox::backdrop {
    background: rgb(0 0 0 / 0.8);
}

.lightbox-bar {
    display: flex;
    align-items: center;
    gap: 2px;
    padding: 6px 6px 6px 16px;
}

.lightbox-title {
    flex: 1;
    min-width: 0;
    color: var(--heading);
    font-size: 16px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.lightbox-count {
    color: var(--muted);
    font-size: 13px;
    font-variant-numeric: tabular-nums;
    margin-right: 8px;
}

.lightbox-stage {
    aspect-ratio: var(--aspect);
    background: var(--stage);
}

.lightbox-caption {
    padding: 10px 16px 14px;
    color: var(--muted);
    font-size: 14px;
    line-height: 1.5;
}

.panel figcaption {
    padding: 10px 2px 0;
    font-size: 14px;
    color: var(--muted);
    line-height: 1.5;
}

.panel figcaption b {
    display: block;
    color: var(--heading);
    font-size: 15px;
    font-weight: 600;
    margin-bottom: 2px;
}

.hint {
    color: var(--muted);
    font-size: 13px;
    margin: -12px 0 16px;
}

.pager {
    display: flex;
    justify-content: space-between;
    gap: 16px;
    margin-top: 36px;
    padding-top: 16px;
    border-top: 1px solid var(--line);
    font-size: 14px;
}

.pager a {
    text-decoration: none;
}

.pager a:hover {
    text-decoration: underline;
}

.pager .next {
    margin-left: auto;
}

/* Home page */

.page .concept-group {
    color: var(--muted);
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    margin: 20px 0 6px;
}

.concept-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 1px;
    background: var(--line);
    border: 1px solid var(--line);
    border-radius: 6px;
    overflow: hidden;
}

.concept-card {
    display: block;
    padding: 14px 16px;
    background: var(--bg);
    color: var(--muted);
    text-decoration: none;
    font-size: 14px;
}

.concept-card b {
    display: block;
    color: var(--heading);
    font-size: 16px;
    margin-bottom: 2px;
}

.concept-card:hover {
    background: var(--stage);
}

.concept-card:hover b {
    color: var(--accent);
}

@media (max-width: 768px) {
    .app-container {
        flex-direction: column;
    }

    .sidebar {
        width: 100%;
        height: auto;
        max-height: 30vh;
    }

    .page {
        padding: 16px;
    }

    .panel.wide {
        grid-column: auto;
    }
}

::-webkit-scrollbar {
    width: 10px;
}

::-webkit-scrollbar-track {
    background: var(--bg);
}

::-webkit-scrollbar-thumb {
    background: #333;
    border-radius: 5px;
}