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

:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --text-color: #1f2937;
    --bg-color: #ffffff;
    --section-bg: #f9fafb;
    --border-color: #e5e7eb;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --muted: #6b7280;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.top-nav {
    position: sticky;
    top: 0;
    z-index: 20;
    background-color: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
}

.nav-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.brand {
    font-weight: 700;
    font-size: 1.2rem;
    color: var(--primary-color);
    letter-spacing: -0.01em;
}

.nav-links {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.nav-links a {
    color: var(--text-color);
    text-decoration: none;
    font-weight: 500;
    padding: 8px 10px;
    border-radius: 8px;
    transition: background-color 0.2s ease, color 0.2s ease;
}

.nav-links a:hover {
    background-color: var(--section-bg);
    color: var(--secondary-color);
}

/* Header */
.header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 60px 0;
    text-align: center;
    box-shadow: var(--shadow-lg);
}

.title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 10px;
    letter-spacing: -0.02em;
}

.subtitle {
    font-size: 1.6rem;
    margin-bottom: 18px;
    opacity: 0.98;
    font-weight: 600;
    text-align: center;
    max-width: 100%;
}

.author-line {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 8px;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 26px;
    font-size: 0.98rem;
    line-height: 1.6;
}

.author-line .dot {
    opacity: 0.8;
}

.author-line .org {
    font-weight: 600;
}

.author-contact {
    color: #e0e7ff;
    text-decoration: none;
    font-weight: 600;
}

.author-link {
    color: #e0e7ff;
    text-decoration: none;
    font-weight: 700;
}

.author-link:hover {
    text-decoration: underline;
}

.author-contact:hover {
    text-decoration: underline;
}

.links {
    display: flex;
    gap: 15px;
    justify-content: center;
    flex-wrap: wrap;
}

.btn {
    display: inline-block;
    padding: 12px 24px;
    background-color: rgba(255, 255, 255, 0.18);
    color: white;
    text-decoration: none;
    border-radius: 8px;
    transition: all 0.3s ease;
    border: 2px solid rgba(255, 255, 255, 0.25);
    font-weight: 500;
}

.btn:hover {
    background-color: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.btn-primary {
    background-color: #ffffff;
    color: var(--secondary-color);
    border-color: rgba(255, 255, 255, 0.6);
}

.btn-secondary {
    background-color: rgba(255, 255, 255, 0.18);
}

.btn-soon {
    position: relative;
}

.btn-soon::after {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: 8px;
    box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.18);
    pointer-events: none;
}

.btn-ghost {
    background-color: transparent;
    border-color: rgba(255, 255, 255, 0.35);
}

.btn-outline {
    background-color: transparent;
    border-color: rgba(255, 255, 255, 0.6);
}

.btn.disabled,
.btn[aria-disabled="true"] {
    cursor: not-allowed;
    opacity: 0.65;
    box-shadow: none;
    transform: none;
    pointer-events: none;
}

/* Introduction Section */
.intro-section {
    padding: 60px 0;
    background-color: var(--bg-color);
}

.intro-section h2 {
    font-size: 2rem;
    margin-bottom: 16px;
    color: var(--primary-color);
}

.intro-section p {
    font-size: 1.05rem;
    line-height: 1.8;
    margin-bottom: 15px;
    color: #4b5563;
}

.meta-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 16px;
    margin-bottom: 32px;
}

.meta-single {
    margin-bottom: 32px;
}

.meta-stack {
    display: flex;
    flex-direction: column;
    gap: 16px;
    margin-bottom: 32px;
}

.meta-card {
    background-color: var(--section-bg);
    padding: 20px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow);
}

.meta-card h3 {
    font-size: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    color: var(--secondary-color);
    margin-bottom: 8px;
}

.meta-card p {
    margin: 0;
    color: var(--text-color);
    line-height: 1.6;
}

.meta-card a {
    color: var(--secondary-color);
    text-decoration: none;
}

.meta-card.simple {
    display: flex;
    flex-direction: column;
    gap: 8px;
    padding: 18px;
    box-shadow: var(--shadow);
}

.meta-line {
    margin: 0;
    color: var(--text-color);
    line-height: 1.5;
}

.meta-card.compact {
    padding: 16px 18px;
    box-shadow: var(--shadow);
}

.meta-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 10px;
}

.meta-subtext {
    color: var(--muted);
    font-size: 0.95rem;
}

.contact-link {
    font-weight: 600;
    color: var(--secondary-color);
    text-decoration: none;
    padding: 8px 12px;
    border-radius: 10px;
    border: 1px solid var(--border-color);
    background-color: white;
    box-shadow: var(--shadow);
    transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}

.contact-link:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-lg);
    border-color: var(--secondary-color);
}

.author-list {
    display: flex;
    flex-wrap: wrap;
    gap: 8px 12px;
}

.author-list.compact {
    gap: 6px 10px;
}

.author-pill {
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 999px;
    padding: 6px 12px;
    box-shadow: var(--shadow);
    font-size: 0.95rem;
    color: var(--text-color);
}

.author-list.compact .author-pill {
    padding: 5px 10px;
    font-size: 0.92rem;
    box-shadow: none;
}

.info-list {
    display: grid;
    gap: 8px;
    color: var(--text-color);
}

.content-stack {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 30px;
}

.content-block {
    background: white;
    padding: 24px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.contribution-list {
    list-style: disc;
    padding-left: 20px;
    color: #4b5563;
    line-height: 1.7;
}

.contribution-list li {
    margin-bottom: 10px;
}

/* Video Sections */
.video-section {
    padding: 60px 0;
    background-color: var(--section-bg);
}

.video-section:nth-child(even) {
    background-color: var(--bg-color);
}

.video-section h2 {
    font-size: 2rem;
    margin-bottom: 40px;
    color: var(--primary-color);
    text-align: center;
}

.section-lead {
    max-width: 900px;
    margin: -18px auto 28px auto;
    text-align: center;
    color: var(--muted);
    font-size: 1.05rem;
    line-height: 1.7;
}

.badge {
    display: inline-block;
    padding: 4px 10px;
    border-radius: 999px;
    font-weight: 700;
    font-size: 0.9rem;
    vertical-align: baseline;
    border: 1px solid transparent;
}

.badge.baseline {
    background-color: #f3f4f6;
    color: #374151;
    border-color: #e5e7eb;
}

.badge.dancegrpo {
    background-color: #ecfccb;
    color: #3f6212;
    border-color: #d9f99d;
}

.badge.ours {
    background-color: #dbeafe;
    color: #1d4ed8;
    border-color: #93c5fd;
}

.comparison-subsection {
    margin-top: 34px;
}

.subsection-header {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 14px;
    padding: 0 2px;
}

.subsection-header h3 {
    font-size: 1.35rem;
    color: var(--text-color);
    letter-spacing: -0.01em;
}

.subsection-link {
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.95rem;
}

.subsection-link:hover {
    text-decoration: underline;
}

/* Video Grid */
.video-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-top: 30px;
}

.video-card {
    background: white;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.video-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.video-wrapper {
    position: relative;
    width: 100%;
    padding-top: 56.25%; /* 16:9 aspect ratio */
    background-color: #000;
    overflow: hidden;
}

.video-wrapper video {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.video-info {
    padding: 20px;
}

.video-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-color);
}

.video-description {
    font-size: 0.95rem;
    color: #6b7280;
    line-height: 1.5;
}

/* Comparison Grid */
.comparison-grid {
    display: grid;
    gap: 40px;
    margin-top: 30px;
}

.comparison-group {
    background: white;
    border-radius: 12px;
    padding: 30px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.comparison-title {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--text-color);
}

.comparison-prompt {
    font-size: 1rem;
    color: #6b7280;
    margin-bottom: 25px;
    font-style: italic;
}

.comparison-videos {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

.comparison-item {
    text-align: center;
}

.comparison-item video {
    width: 100%;
    border-radius: 8px;
    box-shadow: var(--shadow);
    margin-bottom: 10px;
}

.comparison-item video:focus {
    outline: 3px solid rgba(37, 99, 235, 0.25);
    outline-offset: 3px;
}

.comparison-label {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-color);
    padding: 8px 12px;
    background-color: var(--section-bg);
    border-radius: 6px;
    display: inline-block;
}

.comparison-label.baseline {
    background-color: #f3f4f6;
    color: #374151;
}

.comparison-label.dancegrpo {
    background-color: #ecfccb;
    color: #3f6212;
}

.comparison-label.ours {
    background-color: #dbeafe;
    color: #1d4ed8;
}

/* Footer */
.footer {
    background-color: var(--text-color);
    color: white;
    padding: 30px 0;
    text-align: center;
}

.footer p {
    opacity: 0.8;
}

.toast {
    position: fixed;
    left: 50%;
    bottom: 22px;
    transform: translateX(-50%);
    background: rgba(15, 23, 42, 0.92);
    color: #e2e8f0;
    padding: 10px 14px;
    border-radius: 12px;
    box-shadow: var(--shadow-lg);
    border: 1px solid rgba(148, 163, 184, 0.25);
    max-width: calc(100% - 24px);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.2s ease, transform 0.2s ease;
    font-weight: 600;
}

.toast.show {
    opacity: 1;
    transform: translateX(-50%) translateY(-2px);
}

.citation-section {
    padding: 60px 0;
    background-color: var(--bg-color);
}

.citation-section p {
    color: var(--muted);
}

.bibtex {
    margin-top: 20px;
    background-color: #0f172a;
    color: #e2e8f0;
    padding: 20px;
    border-radius: 12px;
    overflow-x: auto;
    font-size: 0.95rem;
    line-height: 1.6;
    box-shadow: var(--shadow);
}

/* Responsive Design */
@media (max-width: 768px) {
    .title {
        font-size: 2rem;
    }
    
    .subtitle {
        font-size: 1.15rem;
    }

    .video-grid {
        grid-template-columns: 1fr;
    }

    .comparison-videos {
        grid-template-columns: 1fr;
    }

    .nav-content {
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
        height: auto;
        padding: 10px 0;
    }

    .nav-links {
        width: 100%;
    }

    .subsection-header {
        flex-direction: column;
        align-items: flex-start;
    }
}

/* Keep hero subtitle on one line on wider screens */
@media (min-width: 900px) {
    .subtitle {
        white-space: nowrap;
        display: inline-block; /* center the actual text width under the title */
        max-width: none;
    }
}

/* Loading Animation */
.loading {
    text-align: center;
    padding: 40px;
    color: #6b7280;
}

.loading::after {
    content: '...';
    animation: dots 1.5s steps(4, end) infinite;
}

@keyframes dots {
    0%, 20% { content: '.'; }
    40% { content: '..'; }
    60%, 100% { content: '...'; }
}