:root {
    --primary-color: #0d6efd; /* Bootstrap Blue */
    --secondary-color: #6c757d;
    --light-bg: #f8f9fa;
    --dark-text: #212529;
    --light-text: #ffffff;
}

body {
    font-family: 'Roboto', sans-serif;
    color: var(--dark-text);
    position: relative;
}

h1, h2, h3, h4, h5, h6, .navbar-brand {
    font-family: 'Montserrat', sans-serif;
    font-weight: 700;
}

.navbar {
    transition: all 0.3s ease;
}

.navbar-scrolled {
    background-color: rgba(255, 255, 255, 0.95);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.hero {
    position: relative;
    height: 80vh;
    min-height: 500px;
    background-image: url('https://placehold.co/1920x1080/003366/FFFFFF?text=AI+&+Knowledge+Graph');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    color: var(--light-text);
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.6);
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 800px;
}

.hero h1 {
    font-size: 3.5rem;
    font-weight: 700;
}

.hero .lead {
    font-size: 1.5rem;
}

.workshop-date {
    font-size: 1.8rem;
    font-weight: 600;
    color: #ffd700;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
    margin: 0;
}

.hero-actions {
    display: flex;
    gap: 15px;
    justify-content: center;
    flex-wrap: wrap;
}

.hero-actions .btn {
    min-width: 200px;
    font-weight: 600;
    transition: all 0.3s ease;
}

.hero-actions .btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.2);
}

@media (max-width: 768px) {
    .hero-actions {
        flex-direction: column;
        align-items: center;
    }
    
    .hero-actions .btn {
        width: 100%;
        max-width: 300px;
    }
}

.section-padding {
    padding: 80px 0;
}

.bg-light {
     background-color: var(--light-bg) !important;
}

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

.section-title h2 {
    font-size: 2.5rem;
    position: relative;
    padding-bottom: 15px;
}

.section-title h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 3px;
    background-color: var(--primary-color);
}

.chair-card {
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 0;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
}

.chair-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.12);
}

.chair-card img {
    width: 120px;
    height: 120px;
    object-fit: cover;
    margin-top: -60px;
    border: 5px solid white;
}

.chair-links a {
    font-size: 1.5rem;
    margin: 0 10px;
    color: var(--secondary-color);
    transition: color 0.3s ease;
}

.chair-links a:hover {
    color: var(--primary-color);
}

.schedule-table th {
    background-color: var(--primary-color);
    color: var(--light-text);
}

.btn-primary {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
    padding: 12px 30px;
    font-weight: 500;
    transition: all 0.3s ease;
}

.btn-primary:hover {
    background-color: #0b5ed7;
    border-color: #0a58ca;
    transform: translateY(-2px);
}

.topic-list {
    list-style: none;
    padding: 0;
}

.topic-list li {
    background-color: #e9ecef;
    display: inline-block;
    padding: 5px 15px;
    margin: 5px;
    border-radius: 50px;
    font-size: 0.9rem;
}

.list-group-item strong {
    color: var(--primary-color);
}

footer {
    background-color: var(--dark-text);
    color: rgba(255, 255, 255, 0.7);
}

footer a {
    color: rgba(255, 255, 255, 0.9);
    text-decoration: none;
}

footer a:hover {
    color: var(--light-text);
    text-decoration: underline;
}

.about-lead-justified { text-align: justify; }

/* Deadline styling */
.deadline-box {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 12px;
    padding: 25px;
    margin-top: 30px;
    box-shadow: 0 10px 30px rgba(102, 126, 234, 0.3);
    animation: subtle-pulse 3s ease-in-out infinite;
}

@keyframes subtle-pulse {
    0%, 100% {
        box-shadow: 0 10px 30px rgba(102, 126, 234, 0.3);
    }
    50% {
        box-shadow: 0 10px 40px rgba(102, 126, 234, 0.5);
    }
}

.deadline-text {
    color: white;
    font-size: 1.1rem;
    margin: 0;
}

.old-deadline {
    text-decoration: line-through;
    opacity: 0.6;
    font-size: 0.95rem;
}

.new-deadline {
    font-size: 1.3rem;
    font-weight: 700;
    color: #ffd700;
    display: inline-block;
    padding: 5px 15px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 8px;
    margin-left: 10px;
    animation: gentle-bounce 2s ease-in-out infinite;
}

@keyframes gentle-bounce {
    0%, 100% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-3px);
    }
}

.submission-highlight {
    position: relative;
    background: linear-gradient(to right, #f8f9fa, #e9ecef);
    border-left: 5px solid #667eea;
    border-radius: 10px;
    padding: 30px;
    margin: 30px 0;
}

/* Agenda Styles */
.agenda-session {
    background: white;
    border-radius: 15px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.08);
    overflow: hidden;
    border: 1px solid #e9ecef;
}

.session-header {
    background: linear-gradient(135deg, var(--primary-color) 0%, #0b5ed7 100%);
    color: white;
    padding: 20px 30px;
    margin: 0;
}

.session-title {
    margin: 0;
    font-size: 1.5rem;
    font-weight: 700;
}

.agenda-item {
    display: flex;
    padding: 25px 30px;
    border-bottom: 1px solid #f8f9fa;
    transition: background-color 0.3s ease;
}

.agenda-item:last-child {
    border-bottom: none;
}

.agenda-item:hover {
    background-color: #f8f9fa;
}

.agenda-item.break-item {
    background: linear-gradient(135deg, #e3f2fd 0%, #f3e5f5 100%);
    border-left: 4px solid #2196f3;
}

.agenda-item.break-item:hover {
    background: linear-gradient(135deg, #d1ecf1 0%, #e8d5e8 100%);
}

.time-badge {
    background: var(--primary-color);
    color: white;
    padding: 8px 16px;
    border-radius: 20px;
    font-weight: 600;
    font-size: 0.9rem;
    min-width: 120px;
    text-align: center;
    margin-right: 25px;
    flex-shrink: 0;
    height: fit-content;
}

.agenda-content {
    flex: 1;
}

.agenda-content h5 {
    color: var(--dark-text);
    margin-bottom: 10px;
    font-weight: 600;
}

.agenda-content p {
    color: #6c757d;
    margin-bottom: 8px;
}

.speaker-info {
    color: var(--primary-color) !important;
    font-size: 0.9rem;
    font-weight: 500;
    margin-bottom: 0 !important;
}

.speaker-info i {
    margin-right: 8px;
}

.talk-list {
    margin-top: 15px;
}

.talk-item {
    background: #f8f9fa;
    padding: 15px;
    margin-bottom: 10px;
    border-radius: 8px;
    border-left: 3px solid var(--primary-color);
}

.talk-item:last-child {
    margin-bottom: 0;
}

.talk-item strong {
    color: var(--dark-text);
    display: block;
    margin-bottom: 8px;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .agenda-item {
        flex-direction: column;
        padding: 20px;
    }
    
    .time-badge {
        margin-right: 0;
        margin-bottom: 15px;
        align-self: flex-start;
    }
    
    .session-header {
        padding: 15px 20px;
    }
    
    .session-title {
        font-size: 1.3rem;
    }
}