* {
    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: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

.default-poster {
    width: 100%;
    height: 400px;
    background: linear-gradient(135deg, #3498db 0%, #2980b9 50%, #1abc9c 100%);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    color: white;
    border-radius: 15px;
    text-align: center;
    padding: 40px;
}

.default-poster h3 {
    font-size: 2.5rem;
    margin-bottom: 20px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.default-poster p {
    font-size: 1.2rem;
    opacity: 0.9;
}

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

/* Navigation Menu */
.navbar {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border-radius: 50px;
    padding: 15px 30px;
    margin-bottom: 30px;
    border: 1px solid rgba(255, 255, 255, 0.2);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
}

.navbar ul {
    list-style: none;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 30px;
}

.navbar li {
    margin: 0;
}

.navbar a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    padding: 10px 20px;
    border-radius: 25px;
    transition: all 0.3s ease;
    position: relative;
}

.navbar a:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}

.navbar a.active {
    background: rgba(255, 255, 255, 0.3);
    font-weight: 600;
}

.header {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    padding: 40px;
    margin-bottom: 30px;
    text-align: center;
    border: 1px solid rgba(255, 255, 255, 0.2);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
}

.header h1 {
    font-size: 3rem;
    margin-bottom: 10px;
    background: linear-gradient(45deg, #fff, #f0f0f0);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.header .subtitle {
    font-size: 1.2rem;
    color: #f0f0f0;
    margin-bottom: 20px;
}

/* Next Session Section */
.next-session {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 15px;
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    text-align: center;
}

.next-session h2 {
    color: #2c3e50;
    margin-bottom: 25px;
    font-size: 2.2rem;
    background: linear-gradient(45deg, #3498db, #2980b9);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.poster-container {
    max-width: 900px;
    margin: 0 auto;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    transition: transform 0.3s ease;
}

.poster-container:hover {
    transform: scale(1.02);
}

.poster-image {
    width: 100%;
    height: auto;
    display: block;
}

.next-session-info {
    margin-top: 20px;
    padding: 20px;
    background: linear-gradient(45deg, #3498db, #2980b9);
    color: white;
    border-radius: 10px;
}

.next-session-date {
    font-size: 1.3rem;
    font-weight: bold;
    margin-bottom: 10px;
}

.next-session-details {
    font-size: 1.1rem;
    line-height: 1.6;
}

.intro-section {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 15px;
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
}

.intro-section h2 {
    color: #2c3e50;
    margin-bottom: 20px;
    font-size: 2rem;
    text-align: center;
}

.intro-section p {
    font-size: 1.1rem;
    color: #555;
    margin-bottom: 15px;
    text-align: justify;
}

.stats-section {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.stat-card {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border-radius: 15px;
    padding: 25px;
    text-align: center;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.stat-number {
    font-size: 2.5rem;
    font-weight: bold;
    color: white;
    margin-bottom: 10px;
}

.stat-label {
    color: #f0f0f0;
    font-size: 1.1rem;
}

.sessions-section {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 15px;
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
}

.sessions-section h2 {
    color: #2c3e50;
    margin-bottom: 25px;
    font-size: 2rem;
    text-align: center;
}

.session-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.session-card {
    background: white;
    border-radius: 12px;
    padding: 25px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border-left: 4px solid #3498db;
}

.session-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
}

.session-date {
    color: #7f8c8d;
    font-size: 0.9rem;
    margin-bottom: 8px;
}

.session-title {
    font-size: 1.3rem;
    font-weight: bold;
    color: #2c3e50;
    margin-bottom: 10px;
}

.session-presenter {
    color: #3498db;
    font-weight: 600;
    margin-bottom: 15px;
}

.youtube-link {
    display: inline-block;
    background: linear-gradient(45deg, #ff6b6b, #ee5a24);
    color: white;
    padding: 8px 16px;
    border-radius: 20px;
    text-decoration: none;
    font-size: 0.9rem;
    transition: all 0.3s ease;
}

.youtube-link:hover {
    background: linear-gradient(45deg, #ee5a24, #ff6b6b);
    transform: scale(1.05);
}

.youtube-link.disabled {
    background: #95a5a6;
    cursor: not-allowed;
    pointer-events: none;
}

.about-section {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 15px;
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
}

.about-section h2 {
    color: #2c3e50;
    margin-bottom: 20px;
    font-size: 2rem;
    text-align: center;
}

.leader-info {
    background: linear-gradient(45deg, #3498db, #2980b9);
    color: white;
    padding: 25px;
    border-radius: 12px;
    text-align: center;
}

.leader-info h3 {
    margin-bottom: 15px;
    font-size: 1.8rem;
}

.leader-info p {
    font-size: 1.1rem;
    line-height: 1.6;
}

.footer {
    text-align: center;
    margin-top: 30px;
    padding: 20px;
    color: rgba(255, 255, 255, 0.8);
}

.loading {
    text-align: center;
    padding: 20px;
    color: #666;
}

.error {
    background: #f8d7da;
    color: #721c24;
    padding: 15px;
    border-radius: 8px;
    margin: 10px 0;
}

/* Responsive Design */
@media (max-width: 768px) {
    .header h1 {
        font-size: 2rem;
    }
    
    .container {
        padding: 15px;
    }
    
    .session-grid {
        grid-template-columns: 1fr;
    }
    
    .navbar ul {
        flex-direction: column;
        gap: 10px;
    }
    
    .navbar {
        padding: 20px;
    }
    
    .poster-container {
        max-width: 100%;
    }
}