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

html {
    scroll-behavior: smooth;
}

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

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

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    margin-bottom: 1rem;
}

h1 {
    font-size: 3rem;
    font-weight: 700;
}

h2 {
    font-size: 2.5rem;
    color: #2d3748;
}

h3 {
    font-size: 1.875rem;
    color: #4a5568;
}

h4 {
    font-size: 1.25rem;
    color: #2d3748;
}

p {
    margin-bottom: 1rem;
    color: #4a5568;
}

a {
    color: #3182ce;
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    color: #2c5282;
}

/* Hero Section */
.hero-section {
    background: url('images/background.png') center/cover no-repeat;
    color: white;
    padding: 8rem 0 6rem;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.1);
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
}

.hero-icon {
    font-size: 4rem;
    margin-bottom: 1rem;
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

.hero-title {
    font-size: 4rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: #2d3748;
    text-shadow: 0 0 5px rgba(255, 255, 255, 1), 
                 0 0 10px rgba(255, 255, 255, 1),
                 0 0 15px rgba(255, 255, 255, 0.9),
                 0 0 20px rgba(255, 255, 255, 0.8),
                 0 0 35px rgba(255, 255, 255, 0.7),
                 0 0 50px rgba(255, 255, 255, 0.5);
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: #4a5568;
    text-shadow: 0 0 5px rgba(255, 255, 255, 1), 
                 0 0 10px rgba(255, 255, 255, 0.9),
                 0 0 15px rgba(255, 255, 255, 0.8),
                 0 0 25px rgba(255, 255, 255, 0.7),
                 0 0 40px rgba(255, 255, 255, 0.5);
}

.hero-description {
    font-size: 1.125rem;
    margin-bottom: 2rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
    color: #2d3748;
    font-weight: 500;
    line-height: 1.6;
    text-shadow: 0 0 5px rgba(255, 255, 255, 1), 
                 0 0 10px rgba(255, 255, 255, 0.9),
                 0 0 15px rgba(255, 255, 255, 0.8),
                 0 0 25px rgba(255, 255, 255, 0.7),
                 0 0 40px rgba(255, 255, 255, 0.5);
}

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

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 2rem;
    border-radius: 50px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    transition: all 0.3s ease;
    cursor: pointer;
    border: none;
    font-size: 0.875rem;
}

.btn-primary {
    background: #4299e1;
    color: white;
    border: 2px solid #4299e1;
    font-weight: 600;
}

.btn-primary:hover {
    background: #3182ce;
    border-color: #3182ce;
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(66, 153, 225, 0.3);
}

.btn-secondary {
    background: transparent;
    color: #2d3748;
    border: 2px solid #2d3748;
    font-weight: 600;
}

.btn-secondary:hover {
    background: #2d3748;
    color: white;
    border-color: #2d3748;
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(45, 55, 72, 0.2);
}

/* Navigation */
.navbar {
    background: white;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

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

.nav-brand {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 700;
    font-size: 1.25rem;
    color: #2d3748;
}

.nav-icon {
    font-size: 1.5rem;
}

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

.nav-menu a {
    font-weight: 500;
    color: #4a5568;
    transition: color 0.3s ease;
}

.nav-menu a:hover {
    color: #667eea;
}

/* Sections */
.section {
    padding: 5rem 0;
}

.section-highlight {
    background: #f7fafc;
}

.section-title {
    text-align: center;
    margin-bottom: 3rem;
    position: relative;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background: linear-gradient(135deg, #667eea, #764ba2);
    border-radius: 2px;
}

/* Abstract Section */
.abstract-content {
    max-width: 800px;
    margin: 0 auto;
    font-size: 1.125rem;
    line-height: 1.8;
}

/* Challenge Section - now Call for Papers */
.challenge-content {
    max-width: 1000px;
    margin: 0 auto;
}

.challenge-info h3 {
    text-align: center;
    margin-bottom: 2rem;
    color: #2d3748;
}

.challenge-info > p {
    text-align: center;
    font-size: 1.125rem;
    margin-bottom: 3rem;
    color: #4a5568;
}

.call-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin: 3rem 0;
}

.submission-section {
    text-align: center;
    margin-top: 3rem;
    padding: 2rem;
    background: white;
    border-radius: 15px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
}

.submission-section h3 {
    margin-bottom: 1rem;
    color: #2d3748;
}

.submission-section p {
    margin-bottom: 2rem;
    color: #4a5568;
}

/* Timeline Section */
.timeline-section {
    margin: 3rem 0;
}

.timeline-section h3 {
    text-align: center;
    margin-bottom: 2rem;
    color: #2d3748;
}

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

.timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 2px;
    height: 100%;
    background: linear-gradient(135deg, #667eea, #764ba2);
}

.timeline-item {
    display: flex;
    align-items: center;
    margin-bottom: 2rem;
    position: relative;
}

.timeline-item:nth-child(odd) {
    flex-direction: row;
}

.timeline-item:nth-child(even) {
    flex-direction: row-reverse;
}

.timeline-date {
    flex: 0 0 200px;
    padding: 1rem;
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    text-align: center;
    border-radius: 10px;
    font-weight: 600;
    font-size: 0.9rem;
    margin: 0 1rem;
}

.timeline-content {
    flex: 1;
    background: white;
    padding: 1.5rem;
    border-radius: 10px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
    margin: 0 1rem;
    position: relative;
}

.timeline-content::before {
    content: '';
    position: absolute;
    top: 50%;
    width: 15px;
    height: 15px;
    background: white;
    border: 3px solid #667eea;
    border-radius: 50%;
    transform: translateY(-50%);
}

.timeline-item:nth-child(odd) .timeline-content::before {
    left: -8px;
}

.timeline-item:nth-child(even) .timeline-content::before {
    right: -8px;
}

.timeline-content h4 {
    margin-bottom: 0.5rem;
    color: #2d3748;
    font-size: 1.1rem;
}

.timeline-content p {
    margin: 0;
    color: #4a5568;
    font-size: 0.95rem;
}

.challenge-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.feature {
    background: white;
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
    text-align: center;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature h4 {
    margin-bottom: 1rem;
    color: #2d3748;
}

.feature p {
    color: #4a5568;
}

/* Schedule Section - Updated to use simple format */
.schedule-content {
    max-width: 800px;
    margin: 0 auto;
}

.schedule-item {
    display: flex;
    gap: 2rem;
    padding: 1.5rem;
    background: white;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    margin-bottom: 1rem;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.schedule-item:hover {
    transform: translateX(5px);
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.15);
}

.time {
    font-weight: 600;
    color: #667eea;
    min-width: 140px;
    font-size: 1.1rem;
    flex-shrink: 0;
}

.event h4 {
    margin-bottom: 0.5rem;
    color: #2d3748;
    font-size: 1.1rem;
}

.event p {
    color: #4a5568;
    margin: 0;
    line-height: 1.5;
}

/* Expandable content styling */
.expandable {
    position: relative;
}

.expand-btn {
    background: #667eea;
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 5px;
    cursor: pointer;
    font-size: 0.8rem;
    margin-top: 0.5rem;
    transition: background 0.3s ease;
}

.expand-btn:hover {
    background: #5a67d8;
}

.abstract-content {
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid #e2e8f0;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}

.abstract-content p {
    font-style: italic;
    color: #4a5568;
    line-height: 1.6;
}

/* Speakers Section */
.speakers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    max-width: 1000px;
    margin: 0 auto;
}

.speaker-card {
    background: white;
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
    text-align: center;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.speaker-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
}

.speaker-image {
    width: 125px;
    height: 125px;
    border-radius: 15%;
    object-fit: cover;
    margin-bottom: 1rem;
    border: 3px solid #667eea;
    transition: transform 0.3s ease;
}

.speaker-image:hover {
    transform: scale(1.05);
}

.speaker-avatar {
    font-size: 4rem;
    margin-bottom: 1rem;
}

.speaker-card h4 {
    margin-bottom: 0.5rem;
    color: #2d3748;
}

.speaker-card h4 a {
    color: #2d3748;
    text-decoration: none;
    transition: color 0.3s ease;
}

.speaker-card h4 a:hover {
    color: #667eea;
}

.speaker-card p {
    color: #4a5568;
    margin-bottom: 0.5rem;
}

.speaker-card p:last-child {
    font-weight: 600;
    color: #667eea;
}

.scholar-link {
    color: #4285f4;
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: color 0.3s ease;
}

.scholar-link:hover {
    color: #1a73e8;
    text-decoration: underline;
}

/* Organizers Section */
.organizers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.organizer-card {
    background: white;
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
    text-align: center;
    transition: all 0.3s ease;
    border: 3px solid transparent;
}

.organizer-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
}

.organizer-card.dimmed {
    opacity: 0.3;
    transform: scale(0.95);
}

.organizer-card.highlighted {
    border: 3px solid;
    border-image: linear-gradient(135deg, #667eea, #764ba2) 1;
    transform: translateY(-5px) scale(1.02);
    box-shadow: 0 10px 30px rgba(102, 126, 234, 0.2);
}

.organizer-image {
    width: 125px;
    height: 125px;
    border-radius: 50%;
    object-fit: cover;
    margin-bottom: 1rem;
    border: 3px solid #667eea;
    transition: transform 0.3s ease;
}

.organizer-image:hover {
    transform: scale(1.05);
}

.organizer-card h4 {
    margin-bottom: 0.5rem;
    color: #2d3748;
    font-size: 1.2rem;
}

.organizer-card h4 a {
    color: #2d3748;
    text-decoration: none;
    transition: color 0.3s ease;
}

.organizer-card h4 a:hover {
    color: #667eea;
}

.organizer-card p {
    color: #4a5568;
    margin-bottom: 0.5rem;
    font-size: 0.95rem;
    line-height: 1.4;
}

/* University Partners Section - now within Organizers */
.universities-section {
    margin: 2rem 0 3rem 0;
    padding: 1rem 0;
}

.universities-grid {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1rem;
    max-width: 1200px;
    margin: 0 auto;
    flex-wrap: nowrap;
    overflow-x: auto;
    padding: 0.5rem 0;
}

.university-logos-combined {
    display: flex;
    gap: 0.5rem;
    background: white;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    padding: 0.5rem;
    transition: all 0.3s ease;
    cursor: pointer;
    flex: 0 0 auto;
}

.university-logos-combined:hover {
    transform: translateY(-3px);
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
}

.university-logos-combined.dimmed {
    opacity: 0.3;
    transform: scale(0.95);
}

.university-logos-combined.active {
    box-shadow: 0 5px 25px rgba(102, 126, 234, 0.3);
    transform: translateY(-5px) scale(1.05);
}

.university-logos-combined .university-logo {
    background: transparent;
    box-shadow: none;
    padding: 0.5rem;
    min-height: 80px;
    min-width: 100px;
    cursor: pointer;
    pointer-events: none;
}

.university-logos-combined .university-logo:hover {
    background: rgba(102, 126, 234, 0.05);
    border-radius: 8px;
    transform: none;
}

.university-logo {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 1rem;
    background: white;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
    min-height: 100px;
    flex: 0 0 auto;
    cursor: pointer;
    min-width: 140px;
}

.university-logo:hover {
    transform: translateY(-3px);
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
}

.university-logo.dimmed {
    opacity: 0.3;
    transform: scale(0.95);
}

.university-logo.active {
    box-shadow: 0 5px 25px rgba(102, 126, 234, 0.3);
    transform: translateY(-5px) scale(1.05);
}

.logo-img {
    max-width: 120px;
    max-height: 60px;
    width: auto;
    height: auto;
    object-fit: contain;
    filter: grayscale(0.2) opacity(0.9);
    transition: filter 0.3s ease;
}

.logo-img:hover {
    filter: grayscale(0) opacity(1);
}

/* Footer */
.footer {
    background: #2d3748;
    color: white;
    padding: 2rem 0;
    text-align: center;
}

.footer p {
    margin: 0;
    color: #a0aec0;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-content {
        padding: 2rem 1.5rem;
        margin: 0 1rem;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.25rem;
    }
    
    .hero-description {
        font-size: 1rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .nav-content {
        flex-direction: column;
        gap: 1rem;
    }
    
    .nav-menu {
        flex-wrap: wrap;
        justify-content: center;
        gap: 1rem;
    }
    
    .schedule-item {
        flex-direction: column;
        gap: 1rem;
    }
    
    .time {
        min-width: auto;
        text-align: center;
        font-size: 1rem;
    }
    
    .section {
        padding: 3rem 0;
    }
    
    h2 {
        font-size: 2rem;
    }
    
    .challenge-features {
        grid-template-columns: 1fr;
    }
    
    .call-features {
        grid-template-columns: 1fr;
    }
    
    .speakers-grid {
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    }
    
    .organizers-grid {
        grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
        gap: 1.5rem;
    }
    
    .universities-grid {
        gap: 0.8rem;
        flex-wrap: nowrap;
        justify-content: flex-start;
        overflow-x: auto;
        padding: 0.5rem;
    }
    
    .university-logos-combined {
        gap: 0.3rem;
        padding: 0.3rem;
    }
    
    .university-logos-combined .university-logo {
        padding: 0.4rem;
        min-height: 70px;
        min-width: 80px;
    }
    
    .university-logo {
        padding: 0.8rem;
        min-height: 80px;
        flex: 0 0 auto;
        min-width: 120px;
    }
    
    .logo-img {
        max-width: 100px;
        max-height: 50px;
    }
    
    /* Timeline responsive for call for papers */
    .timeline::before {
        left: 20px;
    }
    
    .timeline-item {
        flex-direction: column !important;
        align-items: flex-start;
        margin-left: 40px;
    }
    
    .timeline-item:nth-child(even) {
        flex-direction: column !important;
    }
    
    .timeline-date {
        flex: none;
        width: 100%;
        margin: 0 0 1rem 0;
    }
    
    .timeline-content {
        flex: none;
        width: 100%;
        margin: 0;
    }
    
    .timeline-content::before {
        left: -28px !important;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1.125rem;
    }
    
    .hero-description {
        font-size: 1rem;
    }
    
    .container {
        padding: 0 15px;
    }
    
    .feature,
    .speaker-card,
    .organizer-card {
        padding: 1.5rem;
    }
    
    .organizers-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .universities-grid {
        gap: 0.5rem;
        flex-wrap: nowrap;
        justify-content: flex-start;
        overflow-x: auto;
        padding: 0.5rem;
    }
    
    .university-logos-combined {
        gap: 0.2rem;
        padding: 0.2rem;
    }
    
    .university-logos-combined .university-logo {
        padding: 0.3rem;
        min-height: 60px;
        min-width: 70px;
    }
    
    .university-logo {
        padding: 0.6rem;
        min-height: 70px;
        flex: 0 0 auto;
        min-width: 100px;
    }
    
    .logo-img {
        max-width: 80px;
        max-height: 40px;
    }
    
    .schedule-item {
        padding: 1rem;
    }
    
    /* Timeline mobile */
    .timeline-date {
        font-size: 0.8rem;
        padding: 0.8rem;
    }
    
    .timeline-content {
        padding: 1rem;
    }
    
    .timeline-content h4 {
        font-size: 1rem;
    }
    
    .timeline-content p {
        font-size: 0.9rem;
    }
}

/* Smooth animations */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}