:root {
    --primary-color: #1e293b; /* Slate */
    --secondary-color: #a855f7; /* Purple */
    --accent-color: #a855f7; /* Purple for CTAs */
    --accent-hover: #9333ea;
    --highlight-color: #7c3aed; /* Violet for links */
    --dark-color: #0f172a;
    --light-color: #ffffff;
    --gray-100: #f9fafb;
    --gray-200: #f3f4f6;
    --gray-300: #e5e7eb;
    --gray-400: #d1d5db;
    --gray-500: #9ca3af;
    --gray-600: #6b7280;
    --gray-700: #4b5563;
    --font-primary: 'Inter', 'Roboto', sans-serif;
    --font-heading: 'Inter', 'Montserrat', sans-serif;
    --border-radius: 12px;
    --box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -1px rgba(0, 0, 0, 0.04);
}

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

body {
    font-family: var(--font-primary);
    line-height: 1.6;
    color: var(--dark-color);
    background-color: var(--light-color);
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    margin-bottom: 1rem;
    line-height: 1.3;
    font-weight: 700;
}

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

p { margin-bottom: 1rem; }

a {
    color: var(--highlight-color);
    text-decoration: none;
    transition: all 0.3s ease;
}

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

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
    font-size: 1rem;
}

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

.btn-primary:hover {
    background-color: var(--accent-hover);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(168, 85, 247, 0.4);
}

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

.btn-secondary:hover {
    background-color: var(--dark-color);
    color: white;
    transform: translateY(-2px);
}

.btn-outline {
    background-color: transparent;
    color: var(--secondary-color);
    border: 2px solid var(--secondary-color);
}

.btn-outline:hover {
    background-color: var(--secondary-color);
    color: white;
}

.btn-large {
    padding: 1rem 2rem;
    font-size: 1.1rem;
}

.btn-copy {
    background-color: var(--secondary-color);
    color: white;
    padding: 0.5rem 1rem;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 0.9rem;
    margin-top: 1rem;
    transition: all 0.3s ease;
}

.btn-copy:hover {
    background-color: var(--primary-color);
}

/* Utility Classes */
.text-center { text-align: center; }
.mb-1 { margin-bottom: 1rem; }
.mb-2 { margin-bottom: 2rem; }
.mt-1 { margin-top: 1rem; }
.mt-2 { margin-top: 2rem; }
.mt-3 { margin-top: 3rem; }

/* Header */
header {
    background-color: var(--primary-color);
    color: white;
    padding: 1rem 0;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

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

.logo {
    font-family: var(--font-heading);
    font-size: 1.3rem;
    font-weight: 700;
    color: white !important;
    white-space: nowrap;
}

.logo:hover {
    color: var(--gray-300) !important;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 0.25rem;
    align-items: center;
}

.nav-menu li a {
    color: rgba(255, 255, 255, 0.85);
    font-weight: 500;
    padding: 0.5rem 0.75rem;
    border-radius: var(--border-radius);
    transition: all 0.3s ease;
    font-size: 0.9rem;
}

.nav-menu li a:hover {
    color: white;
    background-color: rgba(255, 255, 255, 0.1);
}

.mobile-toggle {
    display: none;
    cursor: pointer;
    color: white;
    font-size: 1.5rem;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #e0c3fc 0%, #8ec5fc 50%, #a0f0ed 100%);
    color: #2d3748;
    padding: 6rem 0 3rem;
    min-height: 50vh;
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(ellipse at 30% 50%, rgba(236, 72, 153, 0.1) 0%, transparent 60%),
                radial-gradient(ellipse at 70% 50%, rgba(168, 85, 247, 0.1) 0%, transparent 60%);
    animation: subtleShift 12s ease-in-out infinite alternate;
}

@keyframes subtleShift {
    0% { transform: translate(0, 0); }
    100% { transform: translate(3%, -2%); }
}

.hero .container {
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 1rem;
    line-height: 1.15;
}

.hero-tagline {
    font-size: 1.5rem;
    font-weight: 300;
    font-style: italic;
    margin-bottom: 2rem;
    color: rgba(30, 50, 80, 0.8);
}

.hero-description {
    font-size: 1.15rem;
    max-width: 800px;
    margin: 0 auto 2rem;
    color: rgba(30, 50, 80, 0.8);
    line-height: 1.8;
}

.scroll-indicator {
    margin-top: 2rem;
    cursor: pointer;
    animation: bounce 2s infinite;
    font-size: 1.5rem;
    color: rgba(30, 50, 80, 0.4);
}

/* Dark hero variant for track pages */
.hero-dark {
    color: white !important;
}

.hero-dark .hero-tagline {
    color: rgba(255, 255, 255, 0.85);
}

.hero-dark .hero-description {
    color: rgba(255, 255, 255, 0.85);
}

.hero-dark .scroll-indicator {
    color: rgba(255, 255, 255, 0.5);
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translateY(0); }
    40% { transform: translateY(-10px); }
    60% { transform: translateY(-5px); }
}

/* Sections */
section {
    padding: 4rem 0;
}

/* Cards */
.card {
    background: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--box-shadow);
    border: 1px solid var(--gray-300);
}

/* Grid Layouts */
.grid-2 {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

/* Track Cards */
.track-card {
    background: white;
    border-radius: 12px;
    padding: 2.5rem;
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.08);
    border: 1px solid var(--gray-300);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    text-align: center;
}

.track-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.12);
}

.track-card .track-icon {
    font-size: 3rem;
    color: var(--secondary-color);
    margin-bottom: 1.5rem;
}

.track-card h3 {
    color: var(--primary-color);
    margin-bottom: 0.75rem;
}

.track-card p {
    color: var(--gray-600);
    margin-bottom: 1.5rem;
}

/* Countdown */
.countdown-container {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 16px;
    padding: 2.5rem;
    text-align: center;
    color: white;
    box-shadow: 0 8px 30px rgba(26, 39, 68, 0.3);
}

.countdown-title {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: white;
}

.countdown-timer {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-bottom: 1rem;
}

.countdown-segment {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.countdown-value {
    font-size: 3rem;
    font-weight: 800;
    font-family: var(--font-heading);
    background: rgba(255, 255, 255, 0.15);
    padding: 0.5rem 1rem;
    border-radius: 10px;
    min-width: 80px;
    text-align: center;
}

.countdown-label {
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-top: 0.5rem;
    opacity: 0.8;
}

.countdown-message {
    margin-top: 1rem;
    font-size: 1rem;
    opacity: 0.9;
    color: white;
}

/* Prize Cards */
.prize-card {
    background: white;
    border-radius: 12px;
    padding: 2rem;
    text-align: center;
    box-shadow: var(--box-shadow);
    border: 1px solid var(--gray-300);
    transition: transform 0.3s ease;
}

.prize-card:hover {
    transform: translateY(-3px);
}

.prize-icon {
    font-size: 2.5rem;
    color: var(--secondary-color);
    margin-bottom: 1rem;
}

/* Team Section */
.team-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 2rem;
    justify-items: center;
}

.team-member {
    text-align: center;
}

.team-member img {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    object-fit: cover;
    margin-bottom: 1rem;
    border: 3px solid var(--gray-300);
    transition: transform 0.3s ease;
}

.team-member img:hover {
    transform: scale(1.05);
}

.team-member h4 {
    margin-bottom: 0.25rem;
    color: var(--primary-color);
}

.team-member p {
    color: var(--gray-600);
    font-size: 0.9rem;
}

/* Citation */
.citation-box {
    background: var(--dark-color);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    position: relative;
    max-width: 800px;
    margin: 0 auto;
}

.citation-box pre {
    overflow-x: auto;
    color: #e2e8f0;
    font-size: 0.85rem;
    line-height: 1.6;
}

.citation-box code {
    font-family: 'Fira Code', 'Courier New', monospace;
}

/* FAQ */
.faq-item {
    margin-bottom: 1rem;
    border: 1px solid var(--gray-300);
    border-radius: var(--border-radius);
    overflow: hidden;
    background: white;
}

.faq-question {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.25rem 1.5rem;
    cursor: pointer;
    font-weight: 600;
    color: var(--primary-color);
    transition: background-color 0.3s ease;
}

.faq-question:hover {
    background-color: var(--gray-100);
}

.faq-question i {
    transition: transform 0.3s ease;
    color: var(--gray-500);
}

.faq-question.active i {
    transform: rotate(180deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
    padding: 0 1.5rem;
}

.faq-question.active + .faq-answer {
    max-height: 1000px;
    padding: 0 1.5rem 1.5rem;
}

/* Timeline */
.timeline {
    position: relative;
    max-width: 800px;
    margin: 2rem auto;
    padding-left: 2rem;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 3px;
    background: linear-gradient(to bottom, var(--secondary-color), #ec4899);
    border-radius: 2px;
}

.timeline-item {
    position: relative;
    margin-bottom: 2rem;
    padding-left: 2rem;
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: -2.45rem;
    top: 0.5rem;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--secondary-color);
    border: 3px solid white;
    box-shadow: 0 0 0 2px var(--secondary-color);
}

.timeline-content {
    background: white;
    padding: 1.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    border: 1px solid var(--gray-300);
}

.timeline-date {
    display: inline-block;
    background: var(--secondary-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

/* Leaderboard Table */
.leaderboard-table {
    width: 100%;
    border-collapse: collapse;
    background: white;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--box-shadow);
}

.leaderboard-table thead {
    background: var(--primary-color);
    color: white;
}

.leaderboard-table th,
.leaderboard-table td {
    padding: 1rem 1.25rem;
    text-align: left;
    border-bottom: 1px solid var(--gray-300);
}

.leaderboard-table tbody tr:hover {
    background-color: var(--gray-100);
}

.leaderboard-table tbody tr:nth-child(even) {
    background-color: var(--gray-100);
}

.rank-1 { color: #d69e2e; font-weight: 700; }
.rank-2 { color: #a0aec0; font-weight: 700; }
.rank-3 { color: #c47a30; font-weight: 700; }

/* Tab Navigation */
.tab-container {
    display: flex;
    gap: 0.5rem;
    justify-content: center;
    flex-wrap: wrap;
}

.tab-button {
    padding: 0.75rem 1.5rem;
    border: 2px solid var(--secondary-color);
    background: transparent;
    color: var(--secondary-color);
    border-radius: var(--border-radius);
    cursor: pointer;
    font-weight: 600;
    font-size: 0.95rem;
    transition: all 0.3s ease;
}

.tab-button.active,
.tab-button:hover {
    background: var(--secondary-color);
    color: white;
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* Sponsor Section */
.sponsors-container {
    text-align: center;
}

.sponsor-tier {
    margin-bottom: 2rem;
}

.tier-label {
    font-size: 1.1rem;
    color: var(--gray-600);
    text-transform: uppercase;
    letter-spacing: 2px;
    margin-bottom: 1.5rem;
}

.sponsor-logos {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 3rem;
    flex-wrap: wrap;
}

.sponsor-item {
    padding: 1.5rem 2rem;
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    border: 1px solid var(--gray-300);
}

.sponsor-placeholder {
    font-size: 1.2rem;
    color: var(--gray-500);
    font-style: italic;
}

/* Code Block */
.code-block-container {
    background: var(--dark-color);
    border-radius: var(--border-radius);
    padding: 1.25rem;
    margin: 1rem 0;
    overflow-x: auto;
}

.code-block-container pre {
    margin: 0;
    color: #e2e8f0;
    font-size: 0.9rem;
    line-height: 1.5;
}

.code-block-container code {
    font-family: 'Fira Code', 'Courier New', monospace;
}

/* Metric Cards */
.metric-card {
    background: white;
    border-radius: 12px;
    padding: 1.5rem;
    text-align: center;
    box-shadow: var(--box-shadow);
    border: 1px solid var(--gray-300);
    transition: transform 0.3s ease;
}

.metric-card:hover {
    transform: translateY(-3px);
}

.metric-card .metric-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--secondary-color);
    margin-bottom: 0.25rem;
}

.metric-card .metric-label {
    font-size: 0.85rem;
    color: var(--gray-600);
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* Approach Tag */
.approach-tag {
    display: inline-block;
    background: var(--gray-200);
    color: var(--gray-700);
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
    margin: 0.25rem;
}

/* Footer */
footer {
    background-color: var(--primary-color);
    color: white;
    padding: 3rem 0 1rem;
}

.footer-container {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-column h3 {
    color: white;
    margin-bottom: 1rem;
}

.footer-column p {
    color: rgba(255, 255, 255, 0.7);
    font-size: 0.95rem;
}

.footer-column ul {
    list-style: none;
}

.footer-column ul li {
    margin-bottom: 0.5rem;
}

.footer-column ul li a {
    color: rgba(255, 255, 255, 0.7);
    transition: color 0.3s ease;
}

.footer-column ul li a:hover {
    color: white;
}

.social-links a {
    color: rgba(255, 255, 255, 0.7);
    font-size: 1.25rem;
    margin-right: 1rem;
    transition: color 0.3s ease;
}

.social-links a:hover {
    color: white;
}

.copyright {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.copyright p {
    color: rgba(255, 255, 255, 0.5);
    font-size: 0.85rem;
}

/* Data Table */
.dataset-table {
    overflow-x: auto;
    margin: 1rem 0;
}

.dataset-table table {
    width: 100%;
    border-collapse: collapse;
    background: white;
    border-radius: var(--border-radius);
    overflow: hidden;
}

.dataset-table th,
.dataset-table td {
    padding: 0.75rem 1rem;
    text-align: left;
    border: 1px solid var(--gray-300);
}

.dataset-table thead {
    background: var(--primary-color);
    color: white;
}

.dataset-table tbody tr:nth-child(even) {
    background: var(--gray-100);
}

/* Phase Indicators */
.phase-indicator {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    background: rgba(255, 255, 255, 0.1);
    font-size: 0.85rem;
}

.phase-indicator.active {
    background: rgba(255, 255, 255, 0.25);
}

.phase-indicator.completed {
    opacity: 0.5;
}

.phase-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.5);
}

.phase-indicator.active .phase-dot {
    background: #48bb78;
    box-shadow: 0 0 8px rgba(72, 187, 120, 0.6);
}

.phase-indicator.completed .phase-dot {
    background: rgba(255, 255, 255, 0.3);
}

/* Info box */
.info-box {
    background: #ebf8ff;
    border-left: 4px solid var(--highlight-color);
    padding: 1.25rem;
    border-radius: 0 var(--border-radius) var(--border-radius) 0;
    margin: 1.5rem 0;
}

.info-box p {
    margin: 0;
    color: var(--gray-700);
}

.warning-box {
    background: #fffbeb;
    border-left: 4px solid #d69e2e;
    padding: 1.25rem;
    border-radius: 0 var(--border-radius) var(--border-radius) 0;
    margin: 1.5rem 0;
}

/* Responsive */
@media (max-width: 968px) {
    .nav-menu {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--primary-color);
        padding: 1rem;
        box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
    }

    .nav-menu.active {
        display: flex;
    }

    .nav-menu li a {
        padding: 0.75rem 1rem;
        display: block;
    }

    .mobile-toggle {
        display: block;
    }

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

    .hero-tagline {
        font-size: 1.2rem;
    }

    .grid-2,
    .grid-3 {
        grid-template-columns: 1fr;
    }

    .footer-container {
        grid-template-columns: 1fr;
    }

    .countdown-value {
        font-size: 2rem;
        min-width: 60px;
    }

    .countdown-timer {
        gap: 0.75rem;
    }

    .team-grid {
        grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
        gap: 1.5rem;
    }
}

@media (max-width: 480px) {
    .hero {
        padding: 6rem 0 3rem;
        min-height: auto;
    }

    .hero-title {
        font-size: 1.6rem;
    }

    h2 {
        font-size: 1.5rem;
    }

    section {
        padding: 2.5rem 0;
    }

    .countdown-value {
        font-size: 1.5rem;
        min-width: 50px;
        padding: 0.35rem 0.5rem;
    }
}