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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background: #f8f9fa;
}

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

/* Header Styles */
header {
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
}

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

.logo {
    display: flex;
    align-items: center;
    gap: 15px;
}

.logo img {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    object-fit: cover;
}

.logo-text h1 {
    font-size: 1.8rem;
    color: #2c3e50;
    font-weight: 700;
    margin-bottom: 0;
}

.logo-text p {
    font-size: 0.9rem;
    color: #667eea;
    margin: 0;
}

nav ul {
    display: flex;
    list-style: none;
    gap: 30px;
}

nav a {
    text-decoration: none;
    color: #2c3e50;
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
    padding: 5px 0;
}

nav a:hover {
    color: #667eea;
}

nav a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: 0;
    left: 0;
    background: #667eea;
    transition: width 0.3s ease;
}

nav a:hover::after {
    width: 100%;
}

.mobile-menu-toggle {
    display: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: #2c3e50;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 80px 0;
    min-height: 70vh;
    display: flex;
    align-items: center;
}

.hero-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 50px;
    align-items: center;
}

.hero-text h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 20px;
    line-height: 1.2;
}

.hero-text h2 {
    font-size: 2rem;
    font-weight: 400;
    margin-bottom: 10px;
    opacity: 0.9;
}

.hero-subtitle {
    font-size: 1.3rem;
    margin-bottom: 20px;
    opacity: 0.8;
}

.hero-description {
    font-size: 1.1rem;
    margin-bottom: 30px;
    opacity: 0.9;
}

.hero-buttons {
    display: flex;
    gap: 20px;
}

.btn {
    padding: 12px 30px;
    border-radius: 25px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    display: inline-block;
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background: rgba(255, 255, 255, 0.2);
    color: hsl(0, 0%, 100%);
    border: 2px solid rgba(255, 255, 255, 0.3);
}

.btn-primary:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
}

.btn-secondary {
    background: white;
    color: #667eea;
    border: 2px solid white;
}

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

.congress-info {
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 15px;
    padding: 30px;
    text-align: center;
    backdrop-filter: blur(10px);
}

.congress-info i {
    font-size: 3rem;
    margin-bottom: 15px;
    color: rgba(255, 255, 255, 0.8);
}

.congress-info h3 {
    font-size: 1.5rem;
    margin-bottom: 10px;
}

.congress-info p {
    margin-bottom: 5px;
    opacity: 0.9;
}

/* About Section */
.about {
    padding: 80px 0;
    background: white;
}

.about h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 50px;
    color: #2c3e50;
}

.about-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.about-card {
    background: #f8f9fa;
    padding: 40px 30px;
    border-radius: 15px;
    text-align: center;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid #e9ecef;
}

.about-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.about-card i {
    font-size: 3rem;
    color: #667eea;
    margin-bottom: 20px;
}

.about-card h3 {
    font-size: 1.5rem;
    margin-bottom: 15px;
    color: #2c3e50;
}

.about-card p {
    color: #6c757d;
    line-height: 1.6;
}

/* Topics Section */
.topics {
    padding: 80px 0;
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
}

.topics h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 50px;
    color: #2c3e50;
}

.topics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.topic-card {
    background: white;
    padding: 40px 30px;
    border-radius: 15px;
    text-align: center;
    transition: all 0.3s ease;
    border: 1px solid #e9ecef;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
}

.topic-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
}

.topic-card i {
    font-size: 3rem;
    color: #667eea;
    margin-bottom: 20px;
}

.topic-card h3 {
    font-size: 1.3rem;
    margin-bottom: 10px;
    color: #2c3e50;
}

.topic-card p {
    color: #6c757d;
    font-style: italic;
}

/* Dates Section */
.dates {
    padding: 80px 0;
    background: white;
}

.dates h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 50px;
    color: #2c3e50;
}

.dates-timeline {
    display: flex;
    justify-content: center;
    gap: 50px;
    flex-wrap: wrap;
}

.date-item {
    display: flex;
    align-items: center;
    gap: 20px;
    background: #f8f9fa;
    padding: 30px;
    border-radius: 15px;
    border-left: 4px solid #667eea;
    transition: transform 0.3s ease;
}

.date-item:hover {
    transform: translateX(10px);
}

.date-icon {
    background: #667eea;
    color: white;
    width: 60px;
    height: 60px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
}

.date-content h3 {
    font-size: 1.2rem;
    margin-bottom: 5px;
    color: #2c3e50;
}

.date-content .date {
    font-size: 1.1rem;
    font-weight: 600;
    color: #667eea;
    margin-bottom: 5px;
}

.date-content p {
    color: #6c757d;
    font-size: 0.9rem;
}

/* Organizers Section */
.organizers {
    padding: 80px 0;
    background: #f8f9fa;
}

.organizers h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 50px;
    color: #2c3e50;
}

.organizer-section {
    margin-bottom: 50px;
}

.organizer-section h3 {
    font-size: 1.8rem;
    margin-bottom: 30px;
    color: #495057;
    text-align: center;
}

.organizer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 25px;
}

.organizer-card {
    background: white;
    padding: 25px;
    border-radius: 10px;
    text-align: center;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid #e9ecef;
}

.organizer-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
}

.organizer-card h4 {
    font-size: 1.1rem;
    margin-bottom: 8px;
    color: #2c3e50;
}

.organizer-card p {
    color: #6c757d;
    font-size: 0.9rem;
}

/* Footer */
footer {
    background: #2c3e50;
    color: white;
    padding: 50px 0 20px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-bottom: 30px;
}

.footer-section h3 {
    font-size: 1.2rem;
    margin-bottom: 20px;
    color: #667eea;
}

.footer-section p {
    margin-bottom: 10px;
    opacity: 0.9;
}

.social-links {
    display: flex;
    gap: 15px;
    margin-top: 20px;
}

.social-links a {
    color: white;
    font-size: 1.5rem;
    transition: color 0.3s ease;
}

.social-links a:hover {
    color: #667eea;
}

.contact-info p {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 10px;
}

.contact-info i {
    width: 20px;
    color: #667eea;
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: 8px;
}

.footer-links a {
    color: white;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: #667eea;
}

.footer-dates {
    list-style: none;
}

.footer-dates li {
    margin-bottom: 8px;
    opacity: 0.9;
}

.footer-dates strong {
    color: #667eea;
}

.footer-bottom {
    border-top: 1px solid #495057;
    padding-top: 20px;
    text-align: center;
    opacity: 0.8;
}

/* Responsive Design */
@media (max-width: 768px) {
    .mobile-menu-toggle {
        display: block;
    }
    
    nav ul {
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 20px;
        box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
        display: none;
    }
    
    nav ul.active {
        display: flex;
    }
    
    nav ul li {
        margin-bottom: 10px;
    }
    
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 30px;
    }
    
    .hero-text h1 {
        font-size: 2.2rem;
    }
    
    .hero-text h2 {
        font-size: 1.6rem;
    }
    
    .hero-buttons {
        justify-content: center;
        flex-wrap: wrap;
    }
    
    .about-grid,
    .topics-grid,
    .organizer-grid {
        grid-template-columns: 1fr;
    }
    
    .dates-timeline {
        flex-direction: column;
        align-items: center;
    }
    
    .date-item {
        flex-direction: column;
        text-align: center;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .social-links {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .hero {
        padding: 60px 0;
    }
    
    .hero-text h1 {
        font-size: 1.8rem;
    }
    
    .hero-text h2 {
        font-size: 1.4rem;
    }
    
    .btn {
        padding: 10px 20px;
        font-size: 0.9rem;
    }
    
    .about,
    .topics,
    .dates,
    .organizers {
        padding: 60px 0;
    }
    
    .about h2,
    .topics h2,
    .dates h2,
    .organizers h2 {
        font-size: 2rem;
    }
}