/* Reset et styles de base */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8f9fa;
}

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

/* Header */
.header {
    background: linear-gradient(135deg, #1e3c72 0%, #2a5298 100%);
    color: white;
    padding: 40px 0;
    text-align: center;
}

.logo {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 10px;
}

.logo i {
    margin-right: 15px;
    color: #ffd700;
}

.subtitle {
    font-size: 1.1rem;
    font-weight: 300;
    opacity: 0.9;
}

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

.nav-tabs {
    display: flex;
    list-style: none;
    overflow-x: auto;
}

.nav-tab {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 20px 30px;
    text-decoration: none;
    color: #666;
    border-bottom: 3px solid transparent;
    transition: all 0.3s ease;
    white-space: nowrap;
    min-width: 200px;
}

.nav-tab:hover {
    color: #2a5298;
    background-color: #f8f9fa;
}

.nav-tab.active {
    color: #2a5298;
    border-bottom-color: #2a5298;
    background-color: #f8f9fa;
}

.nav-tab i {
    font-size: 1.5rem;
    margin-bottom: 8px;
}

.nav-tab .date {
    font-size: 0.85rem;
    color: #888;
    font-weight: 400;
}

/* Contenu principal */
.main-content {
    padding: 40px 0;
}

.colloque-section {
    display: none;
}

.colloque-section.active {
    display: block;
}

/* En-tête du colloque */
.colloque-header {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
    background: white;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 5px 20px rgba(0,0,0,0.1);
}

.colloque-image img {
    width: 100%;
    height: 300px;
    object-fit: cover;
}

.colloque-info {
    padding: 40px;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.colloque-info h2 {
    font-size: 1.8rem;
    color: #2a5298;
    margin-bottom: 25px;
    line-height: 1.3;
}

.event-details {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.detail-item {
    display: flex;
    align-items: center;
    font-size: 1.1rem;
}

.detail-item i {
    color: #2a5298;
    margin-right: 12px;
    width: 20px;
}

/* Grille de contenu */
.content-grid {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 40px;
}

/* Cartes de section */
.section-card {
    background: white;
    border-radius: 12px;
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: 0 3px 15px rgba(0,0,0,0.08);
    border-left: 4px solid #2a5298;
}

.section-card h3 {
    color: #2a5298;
    font-size: 1.4rem;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
}

.section-card h3 i {
    margin-right: 12px;
    color: #ffd700;
}

.section-card p {
    margin-bottom: 15px;
    text-align: justify;
    line-height: 1.7;
}

/* Axes de recherche */
.axes-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 25px;
    margin-top: 20px;
}

.axe-item {
    background: #f8f9fa;
    padding: 25px;
    border-radius: 10px;
    border-left: 3px solid #2a5298;
}

.axe-item h4 {
    color: #2a5298;
    margin-bottom: 15px;
    font-size: 1.1rem;
}

.axe-item ul {
    list-style: none;
}

.axe-item li {
    position: relative;
    padding-left: 20px;
    margin-bottom: 8px;
    color: #555;
}

.axe-item li:before {
    content: "▶";
    position: absolute;
    left: 0;
    color: #2a5298;
    font-size: 0.8rem;
}

/* Informations de soumission */
.submission-info {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
    margin-bottom: 25px;
}

.deadline-box, .format-box {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 10px;
    border-left: 3px solid #e74c3c;
}

.format-box {
    border-left-color: #27ae60;
}

.deadline-box h4, .format-box h4 {
    color: #2a5298;
    margin-bottom: 15px;
    font-size: 1.1rem;
}

.deadline-box ul, .format-box ul {
    list-style: none;
}

.deadline-box li, .format-box li {
    padding: 5px 0;
    border-bottom: 1px solid #eee;
}

.deadline-box li:last-child, .format-box li:last-child {
    border-bottom: none;
}

/* Contact */
.contact-info {
    background: #e8f4f8;
    padding: 20px;
    border-radius: 10px;
    margin-top: 20px;
}

.contact-info h4 {
    color: #2a5298;
    margin-bottom: 15px;
}

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

.contact-info i {
    margin-right: 10px;
    color: #2a5298;
    width: 20px;
}

/* Sidebar */
.sidebar .section-card {
    border-left-color: #ffd700;
}

.committee-list {
    list-style: none;
}

.committee-list li {
    padding: 15px 0;
    border-bottom: 1px solid #eee;
}

.committee-list li:last-child {
    border-bottom: none;
}

.committee-list strong {
    color: #2a5298;
    display: block;
    margin-bottom: 5px;
}

.practical-info p {
    margin-bottom: 10px;
}

.practical-info ul {
    margin: 10px 0 15px 20px;
}

/* Footer */
.footer {
    background: #2a5298;
    color: white;
    text-align: center;
    padding: 30px 0;
    margin-top: 60px;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 0 15px;
    }
    
    .header {
        padding: 30px 0;
    }
    
    .logo {
        font-size: 2rem;
    }
    
    .nav-tabs {
        flex-direction: column;
    }
    
    .nav-tab {
        min-width: auto;
        padding: 15px 20px;
    }
    
    .colloque-header {
        grid-template-columns: 1fr;
        gap: 0;
    }
    
    .colloque-info {
        padding: 30px;
    }
    
    .colloque-info h2 {
        font-size: 1.5rem;
    }
    
    .content-grid {
        grid-template-columns: 1fr;
        gap: 30px;
    }
    
    .axes-grid {
        grid-template-columns: 1fr;
    }
    
    .submission-info {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .section-card {
        padding: 20px;
    }
    
    .event-details {
        gap: 10px;
    }
    
    .detail-item {
        font-size: 1rem;
    }
}

@media (max-width: 480px) {
    .colloque-info h2 {
        font-size: 1.3rem;
    }
    
    .section-card h3 {
        font-size: 1.2rem;
    }
    
    .axe-item {
        padding: 20px;
    }
    
    .nav-tab {
        text-align: center;
    }
}

/* Animations */
.section-card {
    opacity: 0;
    transform: translateY(20px);
    animation: fadeInUp 0.6s forwards;
}

.section-card:nth-child(1) { animation-delay: 0.1s; }
.section-card:nth-child(2) { animation-delay: 0.2s; }
.section-card:nth-child(3) { animation-delay: 0.3s; }
.section-card:nth-child(4) { animation-delay: 0.4s; }

@keyframes fadeInUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Amélioration de l'accessibilité */
.nav-tab:focus,
.section-card:focus {
    outline: 2px solid #2a5298;
    outline-offset: 2px;
}

/* Impression */
@media print {
    .navigation,
    .footer {
        display: none;
    }
    
    .colloque-section {
        display: block !important;
        page-break-after: always;
    }
    
    .section-card {
        break-inside: avoid;
        box-shadow: none;
        border: 1px solid #ddd;
    }
}