/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #fafafa;
}

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

/* Header */
.header {
    background: #fff;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: #2563eb;
}

.logo-link {
    text-decoration: none;
    color: inherit;
}

.logo-link:hover {
    color: #1d4ed8;
}

.nav {
    display: flex;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: #64748b;
    font-weight: 500;
    transition: color 0.2s;
}

.nav-link:hover,
.nav-link.active {
    color: #2563eb;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 4rem 0;
    text-align: center;
}

.hero-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.hero-subtitle {
    font-size: 1.25rem;
    opacity: 0.9;
    max-width: 600px;
    margin: 0 auto 2rem auto;
}

.hero-sponsors {
    font-size: 1rem;
    opacity: 0.9;
    max-width: 700px;
    margin: 0 auto;
}

.hero-sponsors a {
    color: #ffffff;
    text-decoration: underline;
    font-weight: 500;
    transition: all 0.2s;
}

.hero-sponsors a:hover {
    color: #f1f5f9;
    text-decoration: none;
}

.hero-sponsors a:visited {
    color: #e2e8f0;
}

.no-break {
    white-space: nowrap;
}

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

.hero-btn {
    display: inline-block;
    padding: 0.75rem 2rem;
    background: white;
    color: #2563eb;
    text-decoration: none;
    border-radius: 50px;
    font-weight: 600;
    transition: all 0.2s;
    border: 2px solid white;
}

.hero-btn:hover {
    background: transparent;
    color: white;
    transform: translateY(-2px);
}

.hero-btn.secondary {
    background: transparent;
    color: white;
    border: 2px solid rgba(255, 255, 255, 0.3);
}

.hero-btn.secondary:hover {
    background: white;
    color: #2563eb;
    border-color: white;
}

/* Hero buttons on white background sections */
.schedule-section .hero-btn.secondary {
    background: transparent;
    color: #2563eb;
    border: 2px solid #2563eb;
}

.schedule-section .hero-btn.secondary:hover {
    background: #2563eb;
    color: white;
    border-color: #2563eb;
}

/* Schedule Section */
.schedule-section {
    padding: 4rem 0;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 600;
    text-align: center;
    margin-bottom: 3rem;
    color: #1e293b;
}

.schedule-controls {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 3rem;
}

.filter-btn {
    padding: 0.75rem 1.5rem;
    border: 2px solid #e2e8f0;
    background: white;
    color: #64748b;
    border-radius: 50px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}

.filter-btn:hover,
.filter-btn.active {
    background: #2563eb;
    color: white;
    border-color: #2563eb;
}

.schedule-grid {
    display: grid;
    gap: 2rem;
    margin-bottom: 4rem;
}

.schedule-item {
    background: white;
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    border: 1px solid #e2e8f0;
    transition: transform 0.2s, box-shadow 0.2s;
}

.schedule-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
}

.schedule-item.past {
    opacity: 0.7;
}

.schedule-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1rem;
}

.speaker-info h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: #1e293b;
    margin-bottom: 0.25rem;
}

.speaker-link {
    color: #2563eb;
    text-decoration: none;
    transition: color 0.2s;
}

.speaker-link:hover {
    color: #1d4ed8;
    text-decoration: underline;
}

.organizer-link {
    color: #2563eb;
    text-decoration: none;
    transition: color 0.2s;
}

.organizer-link:hover {
    color: #1d4ed8;
    text-decoration: underline;
}

.speaker-affiliation {
    color: #64748b;
    font-size: 0.9rem;
}

.event-date {
    text-align: right;
    color: #2563eb;
    font-weight: 500;
}

.event-time {
    font-size: 0.9rem;
    color: #64748b;
}

.talk-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: #1e293b;
    margin-bottom: 0.75rem;
}

.talk-abstract {
    color: #64748b;
    line-height: 1.6;
    margin-bottom: 1rem;
}

.event-details {
    display: flex;
    gap: 2rem;
    font-size: 0.9rem;
    color: #64748b;
}

.event-link {
    color: #2563eb;
    text-decoration: none;
    font-weight: 500;
}

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

/* No events message */
.no-events {
    text-align: center;
    color: #64748b;
    font-style: italic;
    padding: 2rem;
}

/* About Section */
.about-section {
    background: white;
    padding: 4rem 0;
}

.about-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.about-content p {
    font-size: 1.1rem;
    color: #64748b;
    margin-bottom: 3rem;
    line-height: 1.7;
}

.about-content ul {
    text-align: left;
    margin: 2rem 0 3rem 0;
    padding-left: 1.5rem;
    line-height: 1.8;
}

.about-content li {
    margin-bottom: 1rem;
}

.departments-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 0.5rem;
    margin: 1.5rem 0 2rem 0;
    font-size: 0.9rem;
    color: #64748b;
}

.department {
    padding: 0.25rem 0;
}

.questions-heading {
    font-size: 1.25rem;
    font-weight: 600;
    color: #1e293b;
    margin: 2rem 0 1rem 0;
    text-align: center;
}

.about-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.feature {
    text-align: center;
}

.feature h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: #1e293b;
    margin-bottom: 0.75rem;
}

.feature p {
    color: #64748b;
    margin: 0;
}

/* Contact Section */
.contact-section {
    padding: 4rem 0;
    background: #f8fafc;
}

.contact-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.organizers-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    margin: 40px 0;
    text-align: left;
}

.organizer {
    background: white;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.contact-content p {
    font-size: 1.1rem;
    color: #64748b;
    margin-bottom: 2rem;
}

.contact-info {
    display: grid;
    gap: 1rem;
}

.contact-item {
    font-size: 1rem;
    color: #374151;
}

/* Footer */
.footer {
    background: #1e293b;
    color: white;
    padding: 2rem 0;
    text-align: center;
}

/* Navigation text responsive behavior */
.nav-text-mobile {
    display: none;
}

.nav-text-desktop {
    display: inline;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-text-desktop {
        display: none;
    }
    
    .nav-text-mobile {
        display: inline;
    }

    .header-content {
        flex-direction: column;
        gap: 1rem;
    }

    .nav {
        gap: 1rem;
    }

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

    .hero-subtitle {
        font-size: 1rem;
    }

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

    .schedule-controls {
        flex-wrap: wrap;
        gap: 0.5rem;
    }

    .filter-btn {
        padding: 0.5rem 1rem;
        font-size: 0.9rem;
    }

    .schedule-header {
        flex-direction: column;
        gap: 1rem;
    }

    .event-date {
        text-align: left;
    }

    .event-details {
        flex-direction: column;
        gap: 0.5rem;
    }

    .form-row {
        grid-template-columns: 1fr;
    }

    .about-features {
        grid-template-columns: 1fr;
    }

    .organizers-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
}

/* Hidden class for filtering */
.hidden {
    display: none !important;
}