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

body {
    font-family: 'Georgia', 'Times New Roman', Times, serif;
    line-height: 1.6;
    color: #2d3748;
    overflow-x: hidden;
    font-weight: 400;
}

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

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 1);
    backdrop-filter: blur(10px);
    z-index: 1000;
    padding: 1rem 0;
    border-bottom: 1px solid #ffffff;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 700;
    font-size: 1.2rem;
    color: #685959;
    font-family: 'Inter', sans-serif;
}

.cikm-logo {
    height: 80px;
    width: auto;
    object-fit: contain;
}

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

.nav-menu a {
    text-decoration: none;
    color: #2d3748;
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
    font-family: 'Inter', sans-serif;
}

.nav-menu a:hover {
    color: #4a5568;
}

.nav-menu a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: #4a5568;
    transition: width 0.3s ease;
}

.nav-menu a:hover::after {
    width: 100%;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.nav-toggle span {
    width: 25px;
    height: 3px;
    background: #2d3748;
    margin: 3px 0;
    transition: 0.3s;
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: linear-gradient(135deg, #718096 0%, #4a5568 100%);
    color: white;
    position: relative;
}

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

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1rem;
    font-family: 'Georgia', serif;
}

.hero-subtitle {
    font-size: 1.3rem;
    margin-bottom: 2rem;
    opacity: 0.9;
    font-family: 'Georgia', serif;
    font-style: italic;
}

.hero-stats {
    display: flex;
    gap: 2rem;
    margin-bottom: 3rem;
    justify-content: center;
}

.stat {
    text-align: center;
}

.stat i {
    font-size: 2rem;
    display: block;
    margin-bottom: 0.5rem;
    color: #e2e8f0;
}

.stat span {
    font-size: 1.2rem;
    font-weight: 600;
    display: block;
    font-family: 'Inter', sans-serif;
}

.stat small {
    opacity: 0.8;
    font-size: 0.9rem;
    font-family: 'Inter', sans-serif;
}

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

.btn {
    padding: 1rem 2rem;
    border: none;
    border-radius: 4px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    cursor: pointer;
    display: inline-block;
    font-family: 'Inter', sans-serif;
}

.btn-primary {
    background: #e2e8f0;
    color: #2d3748;
}

.btn-primary:hover {
    background: #cbd5e0;
    transform: translateY(-1px);
}

.btn-secondary {
    background: transparent;
    color: white;
    border: 2px solid white;
}

.btn-secondary:hover {
    background: white;
    color: #4a5568;
    transform: translateY(-1px);
}

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

.bg-light {
    background: #f7fafc;
}

.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-header h2 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: #2d3748;
    font-family: 'Georgia', serif;
}

.section-header p {
    font-size: 1.2rem;
    color: #718096;
    max-width: 600px;
    margin: 0 auto;
    font-family: 'Georgia', serif;
    font-style: italic;
}

/* Overview Section */
.overview-text {
    max-width: 800px;
    margin: 0 auto;
}

.overview-text p {
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
    line-height: 1.8;
    color: #4a5568;
    text-align: justify;
}

.overview-text p:last-child {
    margin-bottom: 0;
}

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

.timeline::before {
    content: '';
    position: absolute;
    left: 30px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: #cbd5e0;
}

.timeline-item {
    position: relative;
    margin-bottom: 3rem;
    padding-left: 80px;
}

.timeline-marker {
    position: absolute;
    left: 0;
    top: 0;
    width: 60px;
    height: 60px;
    background: #4a5568;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.2rem;
    z-index: 2;
}

.timeline-content {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    border: 1px solid #e2e8f0;
    transition: transform 0.3s ease;
}

.timeline-content:hover {
    transform: translateX(5px);
}

.timeline-time {
    color: #4a5568;
    font-weight: 600;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 0.5rem;
    font-family: 'Inter', sans-serif;
}

.timeline-content h3 {
    font-size: 1.4rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: #2d3748;
    font-family: 'Georgia', serif;
}

.timeline-content p {
    color: #718096;
    line-height: 1.6;
    margin-bottom: 1rem;
    text-align: justify;
}

.timeline-tags {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.tag {
    background: #edf2f7;
    color: #4a5568;
    padding: 0.3rem 0.8rem;
    border-radius: 4px;
    font-size: 0.8rem;
    font-weight: 500;
    font-family: 'Inter', sans-serif;
}

.timeline-break {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    margin: 2rem 0;
    color: #718096;
    font-weight: 500;
    font-family: 'Inter', sans-serif;
}

.timeline-break i {
    font-size: 1.5rem;
    color: #a0aec0;
}

/* Responsibility Dimensions */
.responsibility-dimensions {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
    margin: 1.5rem 0;
}

.dimension {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.8rem;
    background: #f7fafc;
    border-radius: 4px;
    font-size: 0.9rem;
    font-weight: 500;
    border: 1px solid #e2e8f0;
    font-family: 'Inter', sans-serif;
}

.dimension i {
    color: #4a5568;
}

/* Presenters Section */
.presenters-row {
    display: flex;
    flex-direction: column;
    gap: 0;
    max-width: 1000px;
    margin: 0 auto;
}

.presenter-item {
    background: white;
    padding: 3rem;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    border: 1px solid #e2e8f0;
    display: flex;
    align-items: flex-start;
    gap: 3rem;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    margin-bottom: 2rem;
}

.presenter-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
}

.presenter-photo {
    width: 180px;
    height: 180px;
    border-radius: 8px;
    background: #f7fafc;
    border: 2px solid #e2e8f0;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    color: #a0aec0;
    font-size: 14px;
    text-align: center;
    font-family: 'Inter', sans-serif;
    overflow: hidden;
}

.presenter-photo img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 6px;
}

.presenter-info {
    flex: 1;
}

.presenter-item h4 {
    font-size: 1.4rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: #2d3748;
    font-family: 'Georgia', serif;
}

.presenter-title {
    color: #4a5568;
    font-weight: 500;
    margin-bottom: 0.8rem;
    font-size: 1rem;
    font-family: 'Inter', sans-serif;
}

.presenter-bio {
    color: #718096;
    line-height: 1.6;
    font-size: 0.95rem;
    text-align: justify;
}

.presenter-bio p {
    margin-bottom: 0.8rem;
}

.presenter-bio p:last-child {
    margin-bottom: 0;
}

.presenter-bio strong {
    color: #4a5568;
    font-weight: 600;
}

.presenter-bio ul {
    margin-bottom: 1rem;
    margin-top: 0.5rem;
    padding-left: 1.5rem;
}

.presenter-bio li {
    margin-bottom: 0.3rem;
    line-height: 1.5;
}

.presenter-bio a {
    color: #4a5568;
    text-decoration: underline;
    font-weight: 500;
}

.presenter-bio a:hover {
    color: #2d3748;
    text-decoration: none;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-stats {
        justify-content: center;
        flex-direction: column;
        gap: 1rem;
    }
    
    .timeline::before {
        left: 15px;
    }
    
    .timeline-item {
        padding-left: 50px;
    }
    
    .timeline-marker {
        width: 30px;
        height: 30px;
        font-size: 0.8rem;
    }
    
    .responsibility-dimensions {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .presenter-item {
        flex-direction: column;
        text-align: center;
        gap: 1rem;
    }
    
    .presenter-info {
        text-align: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .responsibility-dimensions {
        grid-template-columns: 1fr;
    }
    
    .presenter-photo {
        width: 140px;
        height: 140px;
    }

    .presenter-photo img {
        width: 100%;
        height: 100%;
        object-fit: cover;
        border-radius: 6px;
    }
}

/* Smooth scrolling */
html {
    scroll-behavior: smooth;
}

/* Custom scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #f1f1f1;
}

::-webkit-scrollbar-thumb {
    background: #4a5568;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #2d3748;
}