/* For licensing see accompanying LICENSE file. Copyright (C) 2026 Apple Inc. All Rights Reserved. */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&display=swap');

:root {
    --bg: #ffffff;
    --text: #111827;
    --text-secondary: #374151;
    --muted: #6b7280;
    --accent: #2563eb;
    --accent-hover: #1d4ed8;
    --accent-light: #eff6ff;
    --accent-subtle: #dbeafe;
    --border: #e5e7eb;
    --border-light: #f3f4f6;
    --card-bg: #f9fafb;
    --section-alt: #f8fafc;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
    --shadow-lg: 0 12px 40px rgba(0,0,0,0.1);
    --shadow-video: 0 8px 32px rgba(0,0,0,0.12);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;
    --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    color: var(--text);
    background: var(--bg);
    line-height: 1.65;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

::selection {
    background: var(--accent-subtle);
    color: var(--accent-hover);
}

/* ── Hero ──────────────────────────────────────────────────────────── */
.hero {
    position: relative;
    background: #000;
    color: white;
    padding: 0;
    text-align: center;
    overflow: hidden;
}

/* Mosaic background */
.hero-mosaic {
    position: absolute;
    inset: 0;
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 6px;
    opacity: 0.6;
    pointer-events: none;
}

.hero-mosaic-track {
    display: flex;
    gap: 6px;
    width: max-content;
    animation: mosaic-scroll 60s linear infinite;
}

.hero-mosaic-track.reverse {
    animation: mosaic-scroll-reverse 60s linear infinite;
}

.hero-mosaic-track img {
    width: 120px;
    height: 150px;
    object-fit: cover;
    border-radius: 8px;
    flex-shrink: 0;
    transition: opacity 0.4s ease, transform 0.4s ease;
}

/* Enable hover on images */
.hero:hover .hero-mosaic {
    pointer-events: auto;
}

.hero-mosaic-track img:hover {
    opacity: 1;
    transform: scale(1.08);
    z-index: 2;
    position: relative;
}

.hero-mosaic:hover .hero-mosaic-track {
    animation-play-state: paused;
}

@keyframes mosaic-scroll {
    0% { transform: translateX(0); }
    100% { transform: translateX(-50%); }
}

@keyframes mosaic-scroll-reverse {
    0% { transform: translateX(-50%); }
    100% { transform: translateX(0); }
}

/* Dark overlay for text readability */
.hero-overlay {
    position: absolute;
    inset: 0;
    background:
        radial-gradient(ellipse at center, rgba(0,0,0,0.3) 0%, rgba(0,0,0,0.6) 100%);
    z-index: 1;
    pointer-events: none;
}

.hero-content {
    position: relative;
    z-index: 2;
    padding: 80px 32px 68px;
}

.hero h1 {
    font-size: 2.2rem;
    font-weight: 700;
    max-width: 900px;
    margin: 20px auto 14px;
    line-height: 1.15;
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, #ffffff 0%, #93c5fd 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-full-title {
    font-size: 2.2rem;
    font-weight: 700;
    opacity: 0.92;
    max-width: 900px;
    margin: 0 auto 6px;
    letter-spacing: 0.01em;
    line-height: 1.5;
    white-space: nowrap;
}

.hero-affiliation {
    font-size: 0.92rem;
    font-weight: 600;
    opacity: 0.65;
    letter-spacing: 0.04em;
    margin: 0 auto 14px;
}

.hero .subtitle {
    font-size: 0.88rem;
    font-weight: 400;
    opacity: 0.45;
    max-width: 640px;
    margin: 0 auto 28px;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.hero .badge {
    display: inline-block;
    background: rgba(255,255,255,0.08);
    border: 1px solid rgba(255,255,255,0.18);
    border-radius: 100px;
    padding: 7px 22px;
    font-size: 0.78rem;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    backdrop-filter: blur(8px);
    margin-bottom: 12px;
}

/* ── Hero authors ─────────────────────────────────────────────────── */
.hero-authors {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 4px 16px;
    max-width: 800px;
    margin: 8px auto 8px;
    font-size: 0.88rem;
    font-weight: 400;
    opacity: 0.75;
    line-height: 1.7;
}

.hero-authors span {
    white-space: nowrap;
}

.author-note {
    color: rgba(255,255,255,0.6);
    font-size: 0.7em;
}

.author-footnote {
    font-size: 0.75rem;
    opacity: 0.45;
    margin: 0 auto 20px;
}

/* ── Hero buttons ─────────────────────────────────────────────────── */
.hero-buttons {
    display: flex;
    gap: 12px;
    justify-content: center;
    margin-top: 4px;
}

.hero-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 24px;
    border-radius: 100px;
    font-size: 0.85rem;
    font-weight: 600;
    text-decoration: none;
    color: white;
    background: rgba(255,255,255,0.12);
    border: 1px solid rgba(255,255,255,0.25);
    backdrop-filter: blur(8px);
    transition: all var(--transition);
    letter-spacing: 0.01em;
}

.hero-btn:hover {
    background: rgba(255,255,255,0.22);
    border-color: rgba(255,255,255,0.4);
    transform: translateY(-1px);
    box-shadow: 0 4px 20px rgba(0,0,0,0.2);
}

.hero-btn svg {
    flex-shrink: 0;
}

/* ── Navigation ────────────────────────────────────────────────────── */
nav {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255,255,255,0.92);
    backdrop-filter: blur(16px) saturate(180%);
    -webkit-backdrop-filter: blur(16px) saturate(180%);
    border-bottom: 1px solid rgba(0,0,0,0.06);
    padding: 0 24px;
}

nav ul {
    display: flex;
    justify-content: center;
    gap: 4px;
    list-style: none;
    max-width: 1100px;
    margin: 0 auto;
    overflow-x: auto;
    padding: 10px 0;
    scrollbar-width: none;
}
nav ul::-webkit-scrollbar { display: none; }

nav a {
    text-decoration: none;
    color: var(--muted);
    font-size: 0.82rem;
    font-weight: 500;
    padding: 7px 16px;
    border-radius: 8px;
    transition: all var(--transition);
    white-space: nowrap;
    letter-spacing: -0.01em;
}

nav a:hover {
    color: var(--accent);
    background: var(--accent-light);
}

nav a.active {
    color: var(--accent);
    background: var(--accent-light);
    font-weight: 600;
}

/* ── Sections ──────────────────────────────────────────────────────── */
section {
    max-width: 1200px;
    margin: 0 auto;
    padding: 64px 32px;
}

section:nth-child(even) {
    background: var(--section-alt);
    max-width: 100%;
    border-top: 1px solid var(--border-light);
    border-bottom: 1px solid var(--border-light);
}
section:nth-child(even) > * {
    max-width: 1200px;
    margin-left: auto;
    margin-right: auto;
}

h2 {
    font-size: 1.65rem;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--text);
    letter-spacing: -0.025em;
    line-height: 1.3;
}

h3 {
    font-size: 1.12rem;
    font-weight: 600;
    margin: 32px 0 12px;
    color: var(--text-secondary);
}

.section-desc {
    color: var(--muted);
    font-size: 0.95rem;
    margin-bottom: 32px;
    max-width: 720px;
    line-height: 1.7;
}

/* ── Section header with number ────────────────────────────────────── */
.section-header {
    display: flex;
    align-items: flex-start;
    gap: 20px;
    margin-bottom: 32px;
}

.section-header .section-desc {
    margin-bottom: 0;
}

.section-number {
    flex-shrink: 0;
    font-size: 2.8rem;
    font-weight: 800;
    line-height: 1;
    letter-spacing: -0.04em;
    background: linear-gradient(135deg, var(--accent) 0%, var(--accent-subtle) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    opacity: 0.35;
    user-select: none;
    padding-top: 2px;
}

/* ── Fade-in animation ─────────────────────────────────────────────── */
.fade-in {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.6s cubic-bezier(0.4, 0, 0.2, 1),
                transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ── Abstract ──────────────────────────────────────────────────────── */
.abstract-text {
    max-width: 800px;
    margin: 0 auto;
    font-size: 0.95rem;
    line-height: 1.8;
    color: var(--text-secondary);
}

/* ── Ava-256 / Internal Dataset browser ────────────────────────────── */
.ava-browser {
    max-width: 900px;
    margin: 0 auto;
}

.ava-method-bar {
    display: flex;
    gap: 6px;
    justify-content: center;
    flex-wrap: nowrap;
    margin-bottom: 20px;
}

.ava-method-btn {
    padding: 7px 14px 7px 11px;
    border: 1.5px solid var(--border);
    border-radius: 100px;
    background: white;
    color: var(--muted);
    font-size: 0.78rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition);
    letter-spacing: -0.01em;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    white-space: nowrap;
}

/* Color dot indicator */
.ava-method-btn::before {
    content: '';
    width: 8px;
    height: 8px;
    border-radius: 50%;
    flex-shrink: 0;
    transition: all var(--transition);
}

/* ── HeadsUp = blue ── */
.ava-method-btn.headsup::before {
    background: #93bbfd;
}
.ava-method-btn.headsup {
    border-color: #bfdbfe;
    color: #3b82f6;
    background: #f0f7ff;
}
.ava-method-btn.headsup:hover {
    border-color: #60a5fa;
    color: #2563eb;
    background: #dbeafe;
}
.ava-method-btn.headsup.active {
    border-color: #2563eb;
    background: #2563eb;
    color: white;
    box-shadow: 0 2px 10px rgba(37,99,235,0.35);
}
.ava-method-btn.headsup.active::before {
    background: rgba(255,255,255,0.8);
}

/* ── Avat3r = warm red ── */
.ava-method-btn.avat3r::before {
    background: #fca5a5;
}
.ava-method-btn.avat3r {
    border-color: #fecaca;
    color: #ef4444;
    background: #fef7f7;
}
.ava-method-btn.avat3r:hover {
    border-color: #f87171;
    color: #dc2626;
    background: #fee2e2;
}
.ava-method-btn.avat3r.active {
    border-color: #dc2626;
    background: #dc2626;
    color: white;
    box-shadow: 0 2px 10px rgba(220,38,38,0.35);
}
.ava-method-btn.avat3r.active::before {
    background: rgba(255,255,255,0.8);
}

/* Visual separator between method groups */
.ava-method-bar .ava-method-btn.avat3r:first-of-type {
    margin-left: 8px;
}
.ava-method-bar .method-separator {
    width: 1px;
    height: 28px;
    background: var(--border);
    align-self: center;
    flex-shrink: 0;
}

.ava-video-stage {
    border-radius: var(--radius-lg);
    overflow: hidden;
    background: #000;
    max-width: 900px;
    margin: 0 auto;
    box-shadow: var(--shadow-video);
}

.ava-video-stage video {
    width: 100%;
    max-height: 500px;
    display: block;
    margin: 0 auto;
}

.ava-subject-bar {
    display: flex;
    gap: 8px;
    margin-top: 16px;
    overflow-x: auto;
    padding: 4px 0 8px;
    justify-content: center;
    flex-wrap: nowrap;
    scrollbar-width: none;
}
.ava-subject-bar::-webkit-scrollbar { display: none; }

.ava-subject {
    flex-shrink: 0;
    width: 72px;
    border-radius: var(--radius-sm);
    overflow: hidden;
    cursor: pointer;
    border: 2px solid transparent;
    opacity: 0.45;
    transition: all var(--transition);
    background: #000;
    text-align: center;
}

.ava-subject canvas {
    width: 100%;
    display: block;
}

.ava-subject span {
    display: block;
    font-size: 0.58rem;
    font-weight: 500;
    color: var(--muted);
    padding: 3px 0;
    background: white;
    letter-spacing: 0.02em;
}

.ava-subject.active {
    border-color: var(--accent);
    opacity: 1;
    box-shadow: 0 0 0 3px var(--accent-subtle);
    transform: translateY(-1px);
}

.ava-subject:hover {
    opacity: 0.8;
    transform: translateY(-1px);
}

/* ── Carousel ──────────────────────────────────────────────────────── */
.carousel {
    position: relative;
    max-width: 900px;
    margin: 0 auto 40px;
}

.carousel.carousel-wide {
    max-width: 1200px;
}

.carousel-stage {
    position: relative;
    background: #000;
    border-radius: var(--radius-lg) var(--radius-lg) 0 0;
    overflow: hidden;
    box-shadow: var(--shadow-video);
}

.carousel-slide {
    display: none;
    width: 100%;
}
.carousel-slide.active {
    display: block;
}
.carousel-slide video {
    width: 100%;
    display: block;
}

.carousel-caption {
    padding: 14px 20px;
    background: white;
    border: 1px solid var(--border);
    border-top: none;
    border-radius: 0 0 var(--radius-lg) var(--radius-lg);
    font-size: 0.88rem;
    font-weight: 500;
    color: var(--text);
    min-height: 52px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.carousel-caption .detail {
    font-weight: 400;
    color: var(--muted);
    font-size: 0.8rem;
    margin-top: 2px;
}

.carousel-caption .counter {
    font-size: 0.75rem;
    color: var(--muted);
    white-space: nowrap;
    margin-left: 16px;
    font-variant-numeric: tabular-nums;
}

/* Arrows */
.carousel-arrow {
    position: absolute;
    top: 50%;
    transform: translateY(-100%);
    z-index: 10;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    border: none;
    background: rgba(255,255,255,0.95);
    box-shadow: 0 2px 12px rgba(0,0,0,0.15);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.3rem;
    color: var(--text);
    transition: all var(--transition);
    backdrop-filter: blur(8px);
}
.carousel-arrow:hover {
    background: white;
    box-shadow: 0 4px 20px rgba(0,0,0,0.2);
    transform: translateY(-100%) scale(1.08);
}
.carousel-arrow.prev { left: 14px; }
.carousel-arrow.next { right: 14px; }

/* Thumbnails */
.carousel-thumbs {
    display: flex;
    gap: 8px;
    margin-top: 16px;
    overflow-x: auto;
    padding: 4px 0 8px;
    justify-content: center;
    flex-wrap: wrap;
    scrollbar-width: none;
}
.carousel-thumbs::-webkit-scrollbar { display: none; }

.carousel-thumb {
    flex-shrink: 0;
    width: 72px;
    border-radius: var(--radius-sm);
    overflow: hidden;
    cursor: pointer;
    border: 2px solid transparent;
    opacity: 0.45;
    transition: all var(--transition);
    position: relative;
    background: var(--card-bg);
    text-align: center;
}

.carousel-thumb canvas {
    width: 100%;
    display: block;
}

.carousel-thumb.active {
    border-color: var(--accent);
    opacity: 1;
    box-shadow: 0 0 0 3px var(--accent-subtle);
    transform: translateY(-1px);
}

.carousel-thumb:hover {
    opacity: 0.8;
    transform: translateY(-1px);
}

.carousel-thumb video,
.carousel-thumb img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    pointer-events: none;
}

.carousel-thumb .thumb-label {
    display: block;
    font-size: 0.58rem;
    font-weight: 500;
    color: var(--muted);
    padding: 3px 0;
    background: white;
    letter-spacing: 0.02em;
    position: static;
}

/* ── Expression Driving browser (wider) ─────────────────────────────── */
.driving-browser {
    max-width: 1200px;
}

.driving-video-stage {
    max-width: 1200px;
}

/* ── Generation Results ────────────────────────────────────────────── */
.generation-video-container {
    max-width: 900px;
    margin: 0 auto;
    border-radius: var(--radius-lg);
    overflow: hidden;
    background: #000;

    box-shadow: var(--shadow-video);
}

.generation-video-container video {
    width: 100%;
    display: block;
}

/* ── Rigging layout: 3 expression cols + subject selector ──────────── */
.rigging-layout {
    display: flex;
    gap: 24px;
    max-width: 1200px;
    margin: 0 auto 40px;
}

.rigging-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
    flex: 1;
    min-width: 0;
}

.rigging-col {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.rigging-col-header {
    text-align: center;
    font-size: 0.88rem;
    font-weight: 600;
    color: var(--text);
    letter-spacing: -0.01em;
    padding-bottom: 4px;
}

.rigging-video-row {
    display: flex;
    align-items: flex-start;
    gap: 0;
}

.rigging-video-row > .rigging-row-label {
    flex-shrink: 0;
    writing-mode: vertical-lr;
    transform: rotate(180deg);
    text-align: center;
    padding: 0 5px;
}

.rigging-video-row > video,
.rigging-video-row > .rigging-video-slot,
.rigging-video-row > .rigging-gt-placeholder {
    flex: 1;
    min-width: 0;
    background: transparent;
    border-radius: 10px;
    border: none;
}

.rigging-row-label {
    font-size: 0.68rem;
    font-weight: 600;
    color: var(--accent);
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

.rigging-gt-video {
    width: 100%;
    display: block;
    border-radius: var(--radius-md);
    border: 1px solid var(--border);
}

.rigging-gt-placeholder {
    background: #0a0a0a;
    border-radius: var(--radius-md);
    border: 1px solid var(--border);
}

.rigging-video-slot {
    position: relative;
}

.rigging-ours-video {
    width: 100%;
    display: none;
    border-radius: var(--radius-md);
    border: 1px solid var(--border);
}

.rigging-ours-video.active {
    display: block;
}

/* Subject selector column */
.rigging-selector {
    flex-shrink: 0;
    width: 96px;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.rigging-subject-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.rigging-subject {
    border-radius: var(--radius-sm);
    overflow: hidden;
    cursor: pointer;
    border: 2px solid transparent;
    opacity: 0.45;
    transition: all var(--transition);
    background: #000;
}

.rigging-subject canvas {
    width: 100%;
    display: block;
}

.rigging-subject.active {
    border-color: var(--accent);
    opacity: 1;
    box-shadow: 0 0 0 3px var(--accent-subtle);
}

.rigging-subject:hover {
    opacity: 0.8;
}

/* ── Citation block ────────────────────────────────────────────────── */
.citation-block {
    position: relative;
    max-width: 900px;
    margin: 0 auto;
    background: #1e293b;
    border-radius: var(--radius-md);
    overflow: hidden;
}

.citation-block pre {
    margin: 0;
    padding: 24px 28px;
    overflow-x: auto;
    scrollbar-width: none;
}

.citation-block pre::-webkit-scrollbar {
    display: none;
}

.citation-block code {
    font-family: 'SF Mono', 'Fira Code', 'Cascadia Code', Consolas, monospace;
    font-size: 0.8rem;
    line-height: 1.7;
    color: #e2e8f0;
    white-space: pre;
}

.citation-copy-btn {
    position: absolute;
    top: 12px;
    right: 12px;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 14px;
    border-radius: 8px;
    border: 1px solid rgba(255,255,255,0.12);
    background: rgba(255,255,255,0.06);
    color: rgba(255,255,255,0.6);
    font-size: 0.75rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition);
    font-family: inherit;
}

.citation-copy-btn:hover {
    background: rgba(255,255,255,0.12);
    color: rgba(255,255,255,0.9);
}

/* ── Footer ────────────────────────────────────────────────────────── */
footer {
    text-align: center;
    padding: 48px 24px;
    background: #0f172a;
    color: rgba(255,255,255,0.5);
    font-size: 0.8rem;
    letter-spacing: -0.01em;
    line-height: 1.7;
}

.footer-content {
    max-width: 600px;
    margin: 0 auto;
}

.footer-title {
    font-size: 1.1rem;
    font-weight: 700;
    color: rgba(255,255,255,0.85);
    letter-spacing: -0.02em;
    margin-bottom: 4px;
}

.footer-separator {
    width: 40px;
    height: 1px;
    background: rgba(255,255,255,0.15);
    margin: 16px auto;
}

.footer-venue {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: rgba(255,255,255,0.35);
}

/* ── Scroll to top ─────────────────────────────────────────────────── */
.scroll-top {
    position: fixed;
    bottom: 28px;
    right: 28px;
    z-index: 90;
    width: 42px;
    height: 42px;
    border-radius: 50%;
    border: 1px solid var(--border);
    background: rgba(255,255,255,0.95);
    backdrop-filter: blur(12px);
    color: var(--text);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-md);
    opacity: 0;
    transform: translateY(12px);
    pointer-events: none;
    transition: all var(--transition);
}

.scroll-top.visible {
    opacity: 1;
    transform: translateY(0);
    pointer-events: auto;
}

.scroll-top:hover {
    background: white;
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}

/* ── Responsive ────────────────────────────────────────────────────── */
@media (max-width: 768px) {
    .hero-content {
        padding: 56px 20px 44px;
    }
    .hero h1 {
        font-size: 1.4rem;
    }
    .hero-full-title {
        font-size: 1.4rem;
    }
    .hero-mosaic-track img {
        width: 80px;
        height: 100px;
    }
    .section-header {
        flex-direction: column;
        gap: 8px;
    }
    .section-number {
        font-size: 2rem;
    }
    section {
        padding: 44px 20px;
    }
    .carousel-arrow {
        width: 36px;
        height: 36px;
        font-size: 1rem;
    }
    .carousel-thumb { width: 60px; }
    .rigging-layout { flex-direction: column; }
    .rigging-grid { grid-template-columns: 1fr; }
    .rigging-selector {
        width: 100%;
        flex-direction: row;
    }
    .rigging-subject-list {
        flex-direction: row;
        flex-wrap: wrap;
    }
    .rigging-subject { width: 60px; }
    nav ul { justify-content: flex-start; }
    .ava-method-btn {
        font-size: 0.75rem;
        padding: 6px 14px;
    }
    .scroll-top {
        bottom: 16px;
        right: 16px;
        width: 36px;
        height: 36px;
    }
}

@media (max-width: 480px) {
    .hero h1 { font-size: 1.2rem; }
    .hero-full-title { font-size: 1.2rem; }
    .hero .subtitle { font-size: 0.75rem; }
    .hero-mosaic-track img {
        width: 64px;
        height: 80px;
    }
    h2 { font-size: 1.35rem; }
    .ava-subject { width: 60px; }
}