:root {
    /* Colors - Premium Dark Theme */
    --bg-base: #0B0F19;
    --bg-surface: rgba(17, 24, 39, 0.7);
    --bg-surface-hover: rgba(31, 41, 55, 0.8);
    
    --primary: #8B5CF6; /* Purple */
    --primary-hover: #7C3AED;
    --secondary: #3B82F6; /* Blue */
    --accent: #10B981; /* Green/Teal accent if needed */
    
    --text-main: #F8FAFC;
    --text-muted: #9CA3AF;
    --text-inverse: #ffffff;
    
    --border-color: rgba(255, 255, 255, 0.1);
    --border-color-hover: rgba(139, 92, 246, 0.3);
    
    --shadow-glow: 0 0 20px rgba(139, 92, 246, 0.15);
    --shadow-card: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);

    /* Typography */
    --font-heading: 'Outfit', sans-serif;
    --font-body: 'Inter', sans-serif;
}

/* Reset & Base */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    background-color: var(--bg-base);
    color: var(--text-main);
    line-height: 1.6;
    overflow-x: hidden;
    position: relative;
}

body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: radial-gradient(circle at 50% 0%, rgba(59, 130, 246, 0.1) 0%, rgba(11, 15, 25, 0) 50%),
                radial-gradient(circle at 100% 50%, rgba(139, 92, 246, 0.08) 0%, rgba(11, 15, 25, 0) 50%);
    z-index: -1;
    pointer-events: none;
}

/* Typography Utilities */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    line-height: 1.2;
}

.gradient-text {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.text-primary {
    color: var(--primary);
}

.text-sm { font-size: 0.875rem; }
.text-xl { font-size: 1.25rem; }
.text-2xl { font-size: 1.5rem; }
.text-3xl { font-size: 1.875rem; }
.font-bold { font-weight: 700; }
.mb-4 { margin-bottom: 1rem; }
.mb-6 { margin-bottom: 1.5rem; }
.mt-4 { margin-top: 1rem; }
.ml-2 { margin-left: 0.5rem; }
.w-full { width: 100%; }
.text-center { text-align: center; }
.text-gray-400 { color: var(--text-muted); }
.pb-24 { padding-bottom: 6rem; }

/* Layout Utilities */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

.section {
    padding: 6rem 0;
}

.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-header h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.section-subtitle {
    color: var(--text-muted);
    font-size: 1.1rem;
    max-width: 600px;
    margin: 0 auto;
}

.divider {
    height: 4px;
    width: 60px;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    margin: 0 auto 1.5rem;
    border-radius: 2px;
}

/* Glassmorphism */
.glass-card {
    background: var(--bg-surface);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 2rem;
    box-shadow: var(--shadow-card);
    transition: all 0.3s ease;
}

.glass-card:hover {
    border-color: var(--border-color-hover);
    box-shadow: var(--shadow-glow);
    transform: translateY(-2px);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.875rem 1.75rem;
    border-radius: 8px;
    font-weight: 600;
    font-family: var(--font-heading);
    text-decoration: none;
    transition: all 0.3s ease;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: var(--text-inverse);
    box-shadow: 0 4px 15px rgba(139, 92, 246, 0.3);
}

.btn-primary:hover {
    box-shadow: 0 6px 20px rgba(139, 92, 246, 0.4);
    transform: translateY(-2px);
    color: var(--text-inverse);
}

.btn-secondary {
    background: transparent;
    color: var(--text-main);
    border: 1px solid var(--border-color);
    backdrop-filter: blur(4px);
}

.btn-secondary:hover {
    border-color: var(--primary);
    background: rgba(139, 92, 246, 0.1);
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    transition: all 0.3s ease;
    padding: 1.5rem 0;
}

.navbar.scrolled {
    background: rgba(11, 15, 25, 0.8);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    text-decoration: none;
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 800;
    letter-spacing: -0.5px;
}

.nav-links {
    display: flex;
    gap: 2rem;
    list-style: none;
}

.nav-links a {
    color: var(--text-main);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: color 0.3s ease;
    position: relative;
}

.nav-links a:hover {
    color: var(--primary);
}

.nav-links a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -4px;
    left: 0;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    transition: width 0.3s ease;
}

.nav-links a:hover::after {
    width: 100%;
}

.mobile-menu-btn {
    display: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-main);
}

.mobile-nav {
    display: none;
    background: var(--bg-surface);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border-color);
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
}

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

.mobile-nav-links {
    list-style: none;
    padding: 1rem 1.5rem;
}

.mobile-nav-links li {
    margin-bottom: 1rem;
}

.mobile-nav-links a {
    color: var(--text-main);
    text-decoration: none;
    font-size: 1.1rem;
    font-weight: 500;
    display: block;
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    padding-top: 5rem;
}

.hero-bg-glow {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 60vw;
    height: 60vw;
    background: radial-gradient(circle, rgba(139, 92, 246, 0.15) 0%, rgba(11, 15, 25, 0) 70%);
    z-index: -1;
    pointer-events: none;
}

.hero-content {
    max-width: 900px;
    margin: 0 auto;
    text-align: center;
    padding: 0 1.5rem;
}

.badge {
    display: inline-block;
    padding: 0.5rem 1rem;
    background: rgba(139, 92, 246, 0.1);
    border: 1px solid var(--primary);
    color: var(--primary);
    border-radius: 999px;
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    letter-spacing: 0.5px;
}

.hero-title {
    font-size: clamp(2.5rem, 5vw, 4.5rem);
    margin-bottom: 1.5rem;
    letter-spacing: -1px;
}

.hero-subtitle {
    font-size: clamp(1.1rem, 2vw, 1.25rem);
    color: var(--text-muted);
    margin-bottom: 2.5rem;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

.hero-meta {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-bottom: 3rem;
}

.meta-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-muted);
    font-size: 1.1rem;
}

.meta-item i {
    color: var(--secondary);
    font-size: 1.3rem;
}

.hero-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

/* About Section */
.about-content p {
    margin-bottom: 1.5rem;
    color: var(--text-muted);
    font-size: 1.1rem;
}

.about-content p:last-child {
    margin-bottom: 0;
}

.highlight-box {
    background: rgba(59, 130, 246, 0.05);
    border-left: 4px solid var(--secondary);
    padding: 1.5rem;
    border-radius: 0 8px 8px 0;
    display: flex;
    gap: 1rem;
}

.highlight-box p {
    color: var(--text-main);
    margin-bottom: 0;
    font-style: italic;
}

/* Topics Section */
.topics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
}

.topic-card {
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    transition: all 0.3s ease;
}

.topic-card:hover {
    background: var(--bg-surface-hover);
    border-color: var(--border-color-hover);
    transform: translateY(-5px);
}

.topic-card i {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    display: block;
}

.topic-card h3 {
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
}

.topic-card p {
    color: var(--text-muted);
    font-size: 0.95rem;
}

/* Timeline/Dates Section */
.dates-section {
    position: relative;
}

.timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
}

.timeline::after {
    content: '';
    position: absolute;
    width: 2px;
    background: var(--border-color);
    top: 0;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
}

.timeline-item {
    position: relative;
    width: 50%;
    margin-bottom: 2rem;
}

.timeline-item:nth-child(odd) {
    left: 0;
    padding-right: 3rem;
}

.timeline-item:nth-child(even) {
    left: 50%;
    padding-left: 3rem;
}

.timeline-dot {
    position: absolute;
    width: 20px;
    height: 20px;
    background: var(--bg-base);
    border: 4px solid var(--primary);
    border-radius: 50%;
    top: 50%;
    transform: translateY(-50%);
    z-index: 1;
}

.timeline-item:nth-child(odd) .timeline-dot {
    right: -10px;
}

.timeline-item:nth-child(even) .timeline-dot {
    left: -10px;
}

.timeline-content {
    padding: 1.5rem;
}

.date-badge {
    display: inline-block;
    color: var(--secondary);
    font-weight: 600;
    font-family: var(--font-heading);
    margin-bottom: 0.5rem;
}

.timeline-content h3 {
    font-size: 1.2rem;
    margin-bottom: 0.25rem;
}

.timeline-content p {
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* Submission Section */
.submission-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
}

.guidelines-list {
    list-style: none;
}

.guidelines-list li {
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    margin-bottom: 1rem;
    color: var(--text-muted);
}

.guidelines-list li i {
    margin-top: 0.25rem;
    flex-shrink: 0;
}

/* Organizers Section */
.organizers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
}

.organizer-card {
    text-align: center;
    padding: 2rem 1.5rem;
}

.organizer-card h3 {
    font-size: 1.2rem;
    margin-bottom: 0.25rem;
}

.org-affiliation {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-bottom: 1.5rem;
    min-height: 40px;
}

.org-links {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

.org-links a {
    color: var(--text-muted);
    font-size: 1.25rem;
    transition: color 0.3s ease;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: rgba(255,255,255,0.05);
}

.org-links a:hover {
    color: var(--primary);
    background: rgba(139, 92, 246, 0.1);
}

/* Footer */
.footer {
    border-top: 1px solid var(--border-color);
    padding: 3rem 0;
    background: rgba(0,0,0,0.2);
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.footer-brand p {
    color: var(--text-muted);
    margin-top: 0.5rem;
    margin-bottom: 2rem;
}

.footer-bottom {
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* Animations */
.fade-in {
    opacity: 0;
    transition: opacity 0.8s ease-out;
}

.fade-in.visible {
    opacity: 1;
}

.fade-in-up {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}

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

.slide-up {
    opacity: 0;
    transform: translateY(40px);
    transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

.slide-up.visible {
    opacity: 1;
    transform: translateY(0);
}

.slide-in-left {
    opacity: 0;
    transform: translateX(-50px);
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}

.slide-in-right {
    opacity: 0;
    transform: translateX(50px);
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}

.slide-in-left.visible, .slide-in-right.visible {
    opacity: 1;
    transform: translateX(0);
}

/* Responsive */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }
    
    .mobile-menu-btn {
        display: block;
    }
    
    .hero-meta {
        flex-direction: column;
        gap: 1rem;
    }
    
    .timeline::after {
        left: 31px;
    }
    
    .timeline-item {
        width: 100%;
        padding-left: 80px !important;
        padding-right: 0 !important;
    }
    
    .timeline-item:nth-child(even) {
        left: 0;
    }
    
    .timeline-dot {
        left: 21px !important;
    }
    
    .section {
        padding: 4rem 0;
    }
}