/* ==========================================================================
   Unsupervised Speech in the Wild Challenge - Stylesheet
   Academic Professional Theme
   ========================================================================== */

/* CSS Custom Properties */
:root {
    /* Colors */
    --color-primary: #1a365d;
    --color-primary-light: #2c5282;
    --color-primary-dark: #0d1b2a;
    --color-accent: #3182ce;
    --color-accent-light: #63b3ed;
    --color-secondary: #718096;
    --color-success: #38a169;
    --color-warning: #d69e2e;

    /* Neutrals */
    --color-white: #ffffff;
    --color-gray-50: #f7fafc;
    --color-gray-100: #edf2f7;
    --color-gray-200: #e2e8f0;
    --color-gray-300: #cbd5e0;
    --color-gray-400: #a0aec0;
    --color-gray-500: #718096;
    --color-gray-600: #4a5568;
    --color-gray-700: #2d3748;
    --color-gray-800: #1a202c;
    --color-gray-900: #171923;

    /* Typography */
    --font-sans: 'Source Sans 3', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-serif: 'Source Serif 4', Georgia, 'Times New Roman', serif;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    --spacing-4xl: 6rem;

    /* Layout */
    --container-max: 1200px;
    --container-narrow: 900px;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 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);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);

    /* Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
}

/* ==========================================================================
   Base Styles
   ========================================================================== */

*, *::before, *::after {
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: var(--font-sans);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--color-gray-700);
    background-color: var(--color-white);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-serif);
    font-weight: 700;
    line-height: 1.3;
    color: var(--color-gray-800);
    margin: 0 0 var(--spacing-md);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

p {
    margin: 0 0 var(--spacing-md);
}

a {
    color: var(--color-accent);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--color-primary);
    text-decoration: underline;
}

ul {
    margin: 0;
    padding: 0;
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
}

strong {
    font-weight: 600;
}

.lead {
    font-size: 1.25rem;
    line-height: 1.7;
    color: var(--color-gray-600);
}

/* ==========================================================================
   Layout
   ========================================================================== */

.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.section {
    padding: var(--spacing-4xl) 0;
}

.section-alt {
    background-color: var(--color-gray-50);
}

.section-title {
    font-size: 2rem;
    text-align: center;
    margin-bottom: var(--spacing-lg);
    color: var(--color-primary);
}

.section-intro {
    text-align: center;
    max-width: 700px;
    margin: 0 auto var(--spacing-2xl);
    color: var(--color-gray-600);
}

/* ==========================================================================
   Header
   ========================================================================== */

.site-header {
    background-color: var(--color-primary);
    color: var(--color-white);
    padding: var(--spacing-md) 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow-md);
}

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

.logo h1 {
    font-family: var(--font-sans);
    font-size: 1.25rem;
    font-weight: 700;
    margin: 0;
    color: var(--color-white);
}

.conference-badge {
    display: inline-block;
    background-color: var(--color-accent);
    color: var(--color-white);
    font-size: 0.75rem;
    font-weight: 600;
    padding: 0.15rem 0.5rem;
    border-radius: var(--radius-sm);
    margin-left: var(--spacing-sm);
    vertical-align: middle;
}

.main-nav ul {
    display: flex;
    gap: var(--spacing-lg);
}

.main-nav a {
    color: var(--color-gray-200);
    font-size: 0.9rem;
    font-weight: 500;
    padding: var(--spacing-sm) 0;
    transition: color var(--transition-fast);
}

.main-nav a:hover {
    color: var(--color-white);
    text-decoration: none;
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-sm);
}

.mobile-menu-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--color-white);
    transition: var(--transition-fast);
}

/* ==========================================================================
   Hero Section
   ========================================================================== */

.hero {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
    color: var(--color-white);
    padding: var(--spacing-4xl) 0;
    text-align: center;
}

.hero-subtitle {
    font-size: 1rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-accent-light);
    margin-bottom: var(--spacing-sm);
}

.hero-title {
    font-size: 3rem;
    font-weight: 700;
    color: var(--color-white);
    margin-bottom: var(--spacing-md);
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.hero-description {
    font-size: 1.25rem;
    color: var(--color-gray-200);
    max-width: 600px;
    margin: 0 auto var(--spacing-xl);
}

.hero-cta {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    margin-bottom: var(--spacing-2xl);
    flex-wrap: wrap;
}

.hero-dates {
    display: flex;
    justify-content: center;
    gap: var(--spacing-2xl);
    flex-wrap: wrap;
}

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

.date-label {
    display: block;
    font-size: 0.85rem;
    color: var(--color-gray-300);
    margin-bottom: var(--spacing-xs);
}

.date-value {
    display: block;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--color-white);
}

/* ==========================================================================
   Buttons
   ========================================================================== */

.btn {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-xl);
    font-family: var(--font-sans);
    font-size: 1rem;
    font-weight: 600;
    text-align: center;
    text-decoration: none;
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    cursor: pointer;
    border: 2px solid transparent;
}

.btn-primary {
    background-color: var(--color-accent);
    color: var(--color-white);
    border-color: var(--color-accent);
}

.btn-primary:hover {
    background-color: var(--color-primary);
    border-color: var(--color-primary);
    color: var(--color-white);
    text-decoration: none;
}

.btn-secondary {
    background-color: transparent;
    color: var(--color-white);
    border-color: var(--color-white);
}

.btn-secondary:hover {
    background-color: var(--color-white);
    color: var(--color-primary);
    text-decoration: none;
}

.btn-disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.btn-disabled:hover {
    background-color: var(--color-accent);
    border-color: var(--color-accent);
}

/* ==========================================================================
   Content Grid
   ========================================================================== */

.content-grid {
    display: grid;
    grid-template-columns: 1fr 300px;
    gap: var(--spacing-2xl);
    align-items: start;
}

.content-main h3 {
    margin-top: var(--spacing-xl);
    color: var(--color-primary);
}

.info-card {
    background-color: var(--color-gray-50);
    border: 1px solid var(--color-gray-200);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
}

.info-card h4 {
    font-size: 1rem;
    margin-bottom: var(--spacing-md);
    color: var(--color-primary);
}

.info-card ul {
    list-style: disc;
    padding-left: var(--spacing-lg);
}

.info-card li {
    margin-bottom: var(--spacing-sm);
    color: var(--color-gray-600);
    font-size: 0.95rem;
}

/* ==========================================================================
   Task Cards
   ========================================================================== */

.task-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-2xl);
}

.task-card {
    background-color: var(--color-white);
    border: 1px solid var(--color-gray-200);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    text-align: center;
    transition: box-shadow var(--transition-base), transform var(--transition-base);
}

.task-card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}

.task-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 80px;
    height: 80px;
    background-color: var(--color-gray-100);
    border-radius: 50%;
    margin-bottom: var(--spacing-lg);
    color: var(--color-primary);
}

.task-card h3 {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
}

.task-card p {
    color: var(--color-gray-600);
    font-size: 0.95rem;
    margin: 0;
}

.additional-criteria {
    background-color: var(--color-white);
    border: 1px solid var(--color-gray-200);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
}

.additional-criteria h3 {
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.additional-criteria p {
    margin: 0;
    color: var(--color-gray-600);
}

/* ==========================================================================
   Dataset & Baselines
   ========================================================================== */

.data-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-2xl);
}

.dataset-info, .baselines-info {
    background-color: var(--color-gray-50);
    border: 1px solid var(--color-gray-200);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
}

.dataset-info h3, .baselines-info h3 {
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
}

.dataset-info ul {
    list-style: disc;
    padding-left: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.dataset-info li {
    margin-bottom: var(--spacing-sm);
    color: var(--color-gray-600);
}

.baseline-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.baseline-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm) var(--spacing-md);
    background-color: var(--color-white);
    border: 1px solid var(--color-gray-200);
    border-radius: var(--radius-md);
}

.baseline-name {
    font-weight: 600;
    color: var(--color-gray-700);
}

.baseline-status {
    font-size: 0.8rem;
    padding: 0.15rem 0.5rem;
    border-radius: var(--radius-sm);
}

.baseline-status.coming-soon {
    background-color: var(--color-warning);
    color: var(--color-white);
}

.baseline-note {
    font-size: 0.9rem;
    color: var(--color-gray-500);
    font-style: italic;
    margin: 0;
}

/* ==========================================================================
   Rules Section
   ========================================================================== */

.rules-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-2xl);
}

.rule-card {
    background-color: var(--color-white);
    border: 1px solid var(--color-gray-200);
    border-left: 4px solid var(--color-accent);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
}

.rule-card h4 {
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.rule-card p {
    margin: 0;
    color: var(--color-gray-600);
    font-size: 0.95rem;
}

.tracks-info h3 {
    text-align: center;
    color: var(--color-primary);
    margin-bottom: var(--spacing-lg);
}

.tracks-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-lg);
}

.track-card {
    background-color: var(--color-white);
    border: 2px solid var(--color-accent);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    text-align: center;
}

.track-card h4 {
    color: var(--color-accent);
    margin-bottom: var(--spacing-sm);
}

.track-card p {
    margin: 0;
    color: var(--color-gray-600);
}

/* ==========================================================================
   Timeline
   ========================================================================== */

.timeline {
    max-width: var(--container-narrow);
    margin: 0 auto;
}

.timeline-item {
    display: grid;
    grid-template-columns: 100px 1fr;
    gap: var(--spacing-xl);
    padding: var(--spacing-lg) 0;
    border-bottom: 1px solid var(--color-gray-200);
}

.timeline-item:last-child {
    border-bottom: none;
}

.timeline-item.highlight {
    background-color: var(--color-gray-50);
    margin: 0 calc(-1 * var(--spacing-lg));
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    border-bottom: none;
}

.timeline-date {
    text-align: center;
}

.timeline-date .month {
    display: block;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--color-accent);
    text-transform: uppercase;
}

.timeline-date .day {
    display: block;
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--color-primary);
    line-height: 1.2;
}

.timeline-date .year {
    display: block;
    font-size: 0.85rem;
    color: var(--color-gray-500);
}

.timeline-content h4 {
    margin-bottom: var(--spacing-xs);
    color: var(--color-gray-800);
}

.timeline-content p {
    margin: 0;
    color: var(--color-gray-600);
    font-size: 0.95rem;
}

/* ==========================================================================
   Submission Steps
   ========================================================================== */

.steps-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-2xl);
}

.step-card {
    background-color: var(--color-white);
    border: 1px solid var(--color-gray-200);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    text-align: center;
    position: relative;
}

.step-number {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    background-color: var(--color-primary);
    color: var(--color-white);
    font-size: 1.25rem;
    font-weight: 700;
    border-radius: 50%;
    margin-bottom: var(--spacing-md);
}

.step-card h4 {
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.step-card p {
    margin: 0;
    color: var(--color-gray-600);
    font-size: 0.9rem;
}

.submission-cta {
    text-align: center;
}

.submission-cta p {
    color: var(--color-gray-500);
    margin-bottom: var(--spacing-md);
}

/* ==========================================================================
   Ethics Section
   ========================================================================== */

.ethics-content {
    max-width: var(--container-narrow);
    margin: 0 auto;
}

.ethics-content > p {
    text-align: center;
    font-size: 1.1rem;
    margin-bottom: var(--spacing-2xl);
}

.ethics-points {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-xl);
}

.ethics-point {
    background-color: var(--color-gray-50);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
}

.ethics-point h4 {
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.ethics-point p {
    margin: 0;
    color: var(--color-gray-600);
    font-size: 0.95rem;
}

/* ==========================================================================
   Organizers
   ========================================================================== */

.organizers-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-xl);
}

.organizer-card {
    display: flex;
    gap: var(--spacing-lg);
    background-color: var(--color-white);
    border: 1px solid var(--color-gray-200);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
}

.organizer-photo {
    flex-shrink: 0;
    width: 100px;
    height: 100px;
    border-radius: 50%;
    overflow: hidden;
    background-color: var(--color-gray-100);
}

.organizer-photo img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.organizer-info h4 {
    margin-bottom: var(--spacing-xs);
    color: var(--color-gray-800);
}

.organizer-info .affiliation {
    color: var(--color-accent);
    font-weight: 600;
    font-size: 0.9rem;
    margin-bottom: var(--spacing-sm);
}

.organizer-info .bio {
    font-size: 0.9rem;
    color: var(--color-gray-600);
    line-height: 1.5;
    margin-bottom: var(--spacing-sm);
}

.organizer-email {
    font-size: 0.85rem;
    color: var(--color-accent);
}

/* ==========================================================================
   Footer
   ========================================================================== */

.site-footer {
    background-color: var(--color-primary-dark);
    color: var(--color-gray-300);
    padding: var(--spacing-3xl) 0 var(--spacing-xl);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    margin-bottom: var(--spacing-2xl);
}

.footer-info h3 {
    color: var(--color-white);
    font-family: var(--font-sans);
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
}

.footer-info p {
    color: var(--color-gray-400);
    margin: 0;
}

.footer-links {
    display: flex;
    gap: var(--spacing-3xl);
}

.footer-column h4 {
    color: var(--color-white);
    font-family: var(--font-sans);
    font-size: 1rem;
    margin-bottom: var(--spacing-md);
}

.footer-column ul li {
    margin-bottom: var(--spacing-sm);
}

.footer-column a {
    color: var(--color-gray-400);
    font-size: 0.9rem;
}

.footer-column a:hover {
    color: var(--color-white);
}

.footer-bottom {
    border-top: 1px solid var(--color-gray-700);
    padding-top: var(--spacing-lg);
    text-align: center;
}

.footer-bottom p {
    margin: 0;
    font-size: 0.85rem;
    color: var(--color-gray-500);
}

/* ==========================================================================
   Responsive Design
   ========================================================================== */

@media (max-width: 1024px) {
    .content-grid {
        grid-template-columns: 1fr;
    }

    .content-sidebar {
        order: -1;
    }

    .task-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .data-content {
        grid-template-columns: 1fr;
    }

    .steps-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .ethics-points {
        grid-template-columns: 1fr;
    }

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

@media (max-width: 768px) {
    html {
        font-size: 15px;
    }

    .hero-title {
        font-size: 2rem;
    }

    .hero-dates {
        flex-direction: column;
        gap: var(--spacing-md);
    }

    .main-nav {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background-color: var(--color-primary);
        padding: var(--spacing-lg);
        box-shadow: var(--shadow-lg);
    }

    .main-nav.active {
        display: block;
    }

    .main-nav ul {
        flex-direction: column;
        gap: var(--spacing-md);
    }

    .mobile-menu-toggle {
        display: flex;
    }

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

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

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

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

    .timeline-item {
        grid-template-columns: 80px 1fr;
        gap: var(--spacing-md);
    }

    .footer-content {
        flex-direction: column;
        gap: var(--spacing-xl);
    }

    .footer-links {
        flex-direction: column;
        gap: var(--spacing-lg);
    }

    .organizer-card {
        flex-direction: column;
        text-align: center;
    }

    .organizer-photo {
        margin: 0 auto;
    }
}

@media (max-width: 480px) {
    .section {
        padding: var(--spacing-2xl) 0;
    }

    .hero {
        padding: var(--spacing-2xl) 0;
    }

    .hero-cta {
        flex-direction: column;
        align-items: center;
    }

    .btn {
        width: 100%;
        max-width: 280px;
    }
}