/* ========================================
   CSS Variables & Reset
   ======================================== */
:root {
    /* Color Palette - Sophisticated blues with warm accents */
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #3b82f6;
    --secondary: #0f172a;
    --accent: #06b6d4;
    --accent-light: #22d3ee;
    
    /* Neutrals */
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-dark: #0f172a;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --text-light: #94a3b8;
    --border: #e2e8f0;
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #2563eb 0%, #06b6d4 100%);
    --gradient-dark: linear-gradient(135deg, #0f172a 0%, #1e3a5f 100%);
    --gradient-hero: linear-gradient(180deg, rgba(15, 23, 42, 0.95) 0%, rgba(15, 23, 42, 0.85) 100%);
    
    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-display: 'Space Grotesk', sans-serif;
    
    /* Spacing */
    --section-padding: 6rem;
    --container-width: 1200px;
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;
}

/* Reset */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

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

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

/* ========================================
   Network Canvas Background
   ======================================== */
#network-canvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    pointer-events: none;
}

/* ========================================
   Navigation
   ======================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 1rem 2rem;
    transition: var(--transition-base);
    background: transparent;
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.navbar.scrolled .nav-logo,
.navbar.scrolled .nav-links a {
    color: var(--text-primary);
}

.nav-container {
    max-width: var(--container-width);
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    font-family: var(--font-display);
    font-size: 1.25rem;
    font-weight: 600;
    color: white;
    text-decoration: none;
    transition: var(--transition-fast);
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2.5rem;
}

.nav-links a {
    color: rgba(255, 255, 255, 0.9);
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
    transition: var(--transition-fast);
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent);
    transition: var(--transition-base);
}

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

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 5px;
}

.nav-toggle span {
    width: 25px;
    height: 2px;
    background: white;
    transition: var(--transition-fast);
}

.navbar.scrolled .nav-toggle span {
    background: var(--text-primary);
}

/* ========================================
   Hero Section
   ======================================== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    background: var(--gradient-dark);
    padding: 6rem 2rem 4rem;
}

.hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background: 
        radial-gradient(ellipse at 20% 50%, rgba(37, 99, 235, 0.15) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 50%, rgba(6, 182, 212, 0.1) 0%, transparent 50%);
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    max-width: 900px;
}

.hero-badge {
    display: inline-block;
    padding: 0.5rem 1.25rem;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 50px;
    color: rgba(255, 255, 255, 0.9);
    font-size: 0.875rem;
    font-weight: 500;
    letter-spacing: 0.05em;
    margin-bottom: 2rem;
    backdrop-filter: blur(10px);
}

.hero-title {
    margin-bottom: 1.5rem;
}

.title-main {
    display: block;
    font-family: var(--font-display);
    font-size: clamp(3rem, 8vw, 5.5rem);
    font-weight: 700;
    background: linear-gradient(135deg, #ffffff 0%, #94a3b8 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.1;
    letter-spacing: -0.02em;
}

.title-sub {
    display: block;
    font-family: var(--font-display);
    font-size: clamp(1.25rem, 3vw, 1.75rem);
    font-weight: 400;
    color: var(--accent-light);
    margin-top: 0.75rem;
    letter-spacing: 0.02em;
}

.hero-description {
    font-size: 1.125rem;
    color: rgba(255, 255, 255, 0.7);
    max-width: 650px;
    margin: 0 auto 2.5rem;
    line-height: 1.7;
}

.hero-meta {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-bottom: 2.5rem;
    flex-wrap: wrap;
}

.meta-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.95rem;
}

.meta-item svg {
    color: var(--accent);
}

.hero-cta {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 1rem 2.5rem;
    background: var(--gradient-primary);
    color: white;
    text-decoration: none;
    font-weight: 600;
    border-radius: 50px;
    transition: var(--transition-base);
    box-shadow: 0 4px 15px rgba(37, 99, 235, 0.4);
}

.hero-cta:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 25px rgba(37, 99, 235, 0.5);
}

/* ========================================
   Sections - General
   ======================================== */
.section {
    padding: var(--section-padding) 2rem;
}

.section-alt {
    background: var(--bg-secondary);
}

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

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

.section-title {
    font-family: var(--font-display);
    font-size: clamp(2rem, 5vw, 2.75rem);
    font-weight: 600;
    color: var(--secondary);
    margin-bottom: 1rem;
    letter-spacing: -0.02em;
}

.section-line {
    width: 60px;
    height: 4px;
    background: var(--gradient-primary);
    margin: 0 auto;
    border-radius: 2px;
}

/* ========================================
   Overview Section
   ======================================== */
.overview-content {
    display: grid;
    gap: 4rem;
}

.overview-text {
    max-width: 800px;
    margin: 0 auto;
}

.overview-text .lead {
    font-size: 1.25rem;
    color: var(--text-primary);
    line-height: 1.8;
    margin-bottom: 1.5rem;
}

.overview-text p {
    color: var(--text-secondary);
    margin-bottom: 1.25rem;
    line-height: 1.8;
}

.overview-text em {
    color: var(--primary);
    font-style: normal;
    font-weight: 500;
}

.guiding-questions h3 {
    font-family: var(--font-display);
    font-size: 1.5rem;
    color: var(--secondary);
    text-align: center;
    margin-bottom: 2rem;
}

.questions-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}

.question-card {
    background: white;
    padding: 2rem;
    border-radius: 16px;
    border: 1px solid var(--border);
    transition: var(--transition-base);
}

.question-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.08);
    border-color: transparent;
}

.question-icon {
    width: 48px;
    height: 48px;
    background: var(--bg-secondary);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.25rem;
    color: var(--primary);
}

.question-card h4 {
    font-family: var(--font-display);
    font-size: 1.125rem;
    color: var(--secondary);
    margin-bottom: 0.75rem;
}

.question-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* ========================================
   Call for Participation Section
   ======================================== */
.cfp-content {
    max-width: 900px;
    margin: 0 auto;
}

.cfp-content .lead {
    font-size: 1.2rem;
    color: var(--text-primary);
    line-height: 1.8;
    text-align: center;
    margin-bottom: 3rem;
}

.cfp-topics {
    margin-bottom: 3rem;
}

.cfp-topics h3 {
    font-family: var(--font-display);
    font-size: 1.25rem;
    color: var(--secondary);
    margin-bottom: 1.5rem;
}

.topic-list {
    list-style: none;
    display: grid;
    gap: 1rem;
}

.topic-list li {
    position: relative;
    padding-left: 2rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.topic-list li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0.5rem;
    width: 8px;
    height: 8px;
    background: var(--accent);
    border-radius: 50%;
}

.cfp-details {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.detail-card {
    background: white;
    padding: 1.75rem;
    border-radius: 12px;
    border: 1px solid var(--border);
}

.detail-card h4 {
    font-family: var(--font-display);
    font-size: 1rem;
    color: var(--primary);
    margin-bottom: 0.75rem;
}

.detail-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* ========================================
   Organizers Section
   ======================================== */
.organizers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 2rem;
    justify-items: center;
}

.organizer-card {
    text-align: center;
    transition: var(--transition-base);
}

.organizer-card:hover {
    transform: translateY(-4px);
}

.organizer-avatar {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    overflow: hidden;
    margin: 0 auto 1rem;
    background: var(--bg-secondary);
    border: 3px solid var(--border);
    transition: var(--transition-base);
}

.organizer-card:hover .organizer-avatar {
    border-color: var(--primary);
}

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

.organizer-name {
    font-family: var(--font-display);
    font-size: 1rem;
    margin-bottom: 0.25rem;
}

.organizer-name a {
    color: var(--secondary);
    text-decoration: none;
    transition: var(--transition-fast);
}

.organizer-name a:hover {
    color: var(--primary);
}

.organizer-affiliation {
    color: var(--text-secondary);
    font-size: 0.85rem;
}

/* ========================================
   Key Information Section
   ======================================== */
.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 1.5rem;
}

.info-card {
    background: white;
    padding: 2rem;
    border-radius: 16px;
    text-align: center;
    border: 1px solid var(--border);
    transition: var(--transition-base);
}

.info-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.08);
    border-color: var(--primary);
}

.info-icon {
    width: 64px;
    height: 64px;
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.1) 0%, rgba(6, 182, 212, 0.1) 100%);
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.25rem;
    color: var(--primary);
}

.info-card h4 {
    font-family: var(--font-display);
    font-size: 0.9rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.75rem;
}

.info-date {
    font-family: var(--font-display);
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--secondary);
    margin-bottom: 0.25rem;
}

.info-note {
    color: var(--text-light);
    font-size: 0.875rem;
}

/* ========================================
   Footer
   ======================================== */
.footer {
    background: var(--bg-dark);
    color: rgba(255, 255, 255, 0.8);
    padding: 3rem 2rem 1.5rem;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 2rem;
    padding-bottom: 2rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-logo {
    font-family: var(--font-display);
    font-size: 1.25rem;
    font-weight: 600;
    color: white;
}

.footer-brand p {
    color: rgba(255, 255, 255, 0.5);
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

.footer-links {
    display: flex;
    gap: 2rem;
    flex-wrap: wrap;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    font-size: 0.9rem;
    transition: var(--transition-fast);
}

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

.footer-bottom {
    padding-top: 1.5rem;
    text-align: center;
}

.footer-bottom p {
    color: rgba(255, 255, 255, 0.4);
    font-size: 0.85rem;
}

/* ========================================
   Responsive Design
   ======================================== */
@media (max-width: 768px) {
    :root {
        --section-padding: 4rem;
    }
    
    .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 280px;
        height: 100vh;
        background: var(--bg-dark);
        flex-direction: column;
        padding: 5rem 2rem 2rem;
        gap: 1.5rem;
        transition: var(--transition-base);
    }
    
    .nav-links.active {
        right: 0;
    }
    
    .nav-links a {
        color: white;
        font-size: 1.1rem;
    }
    
    .nav-toggle {
        display: flex;
        z-index: 1001;
    }
    
    .nav-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }
    
    .nav-toggle.active span:nth-child(2) {
        opacity: 0;
    }
    
    .nav-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(5px, -5px);
    }
    
    .hero-meta {
        flex-direction: column;
        gap: 1rem;
    }
    
    .questions-grid {
        grid-template-columns: 1fr;
    }
    
    .organizers-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .info-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
    
    .footer-links {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .organizers-grid {
        grid-template-columns: 1fr;
    }
    
    .hero-cta {
        width: 100%;
        justify-content: center;
    }
}

/* ========================================
   Animations
   ======================================== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.hero-content > * {
    animation: fadeInUp 0.8s ease forwards;
}

.hero-badge { animation-delay: 0.1s; }
.hero-title { animation-delay: 0.2s; }
.hero-description { animation-delay: 0.3s; }
.hero-meta { animation-delay: 0.4s; }
.hero-cta { animation-delay: 0.5s; }

/* Scroll animations */
.section-header,
.question-card,
.detail-card,
.organizer-card,
.info-card {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.section-header.visible,
.question-card.visible,
.detail-card.visible,
.organizer-card.visible,
.info-card.visible {
    opacity: 1;
    transform: translateY(0);
}