:root {
    --pastel-blue: #a8d8ea;
    --pastel-green: #c7e9c0;
    --pastel-purple: #d4c4fb;
    --pastel-orange: #ffd8a6;
    --pastel-pink: #f9c5d5;
    --text-dark: #333333;
    --text-light: #666666;
    --white: #ffffff;
    --shadow: rgba(0, 0, 0, 0.1);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: #f9f7f7;
    color: var(--text-dark);
    line-height: 1.6;
}

header {
    background: linear-gradient(135deg, var(--pastel-blue), var(--pastel-purple));
    color: var(--white);
    padding: 2rem 1rem;
    text-align: center;
    box-shadow: 0 4px 12px var(--shadow);
}

.logo-container {
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1rem;
}

.logo {
    width: 80px;
    height: 80px;
    background-color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-right: 1rem;
    box-shadow: 0 4px 8px var(--shadow);
}

.logo i {
    font-size: 2.5rem;
    color: var(--pastel-blue);
}

h1 {
    font-size: 2.2rem;
    margin-bottom: 0.5rem;
}

.subtitle {
    font-size: 1.2rem;
    opacity: 0.9;
}

.admin-link {
    position: absolute;
    top: 2rem;
    right: 2rem;
    color: var(--white);
    text-decoration: none;
    font-size: 0.9rem;
    opacity: 0.8;
    transition: opacity 0.3s ease;
}

.admin-link:hover {
    opacity: 1;
}

nav {
    background-color: var(--white);
    padding: 1rem;
    box-shadow: 0 2px 8px var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
}

.nav-item {
    margin: 0 1rem;
    padding: 0.5rem 1rem;
    border-radius: 30px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 600;
}

.nav-item:hover {
    transform: translateY(-2px);
}

.nav-item.active {
    background-color: var(--pastel-blue);
    color: var(--white);
}

.Physique {
    color: #4a6fa5;
}

.Chimie {
    color: #6b8e23;
}

.projects {
    color: #9b4f96;
}

main {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 1rem;
}

.section {
    display: none;
    animation: fadeIn 0.5s ease;
}

.section.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.section-title {
    text-align: center;
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid var(--pastel-blue);
}

.cards-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
}

.card {
    background-color: var(--white);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 12px var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 16px var(--shadow);
}

.card-header {
    padding: 1.5rem;
    color: var(--white);
    text-align: center;
}

.Physique-card .card-header {
    background-color: var(--pastel-blue);
}

.Chimie-card .card-header {
    background-color: var(--pastel-green);
}

.projects-card .card-header {
    background-color: var(--pastel-purple);
}

.card-body {
    padding: 1.5rem;
}

.card-title {
    font-size: 1.4rem;
    margin-bottom: 0.5rem;
}

.card-description {
    color: var(--text-light);
    margin-bottom: 1rem;
}

.card-list {
    list-style-type: none;
    margin-top: 1rem;
}

.card-list li {
    padding: 0.5rem 0;
    border-bottom: 1px solid #f0f0f0;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

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

.file-icon {
    margin-right: 0.5rem;
    color: var(--pastel-blue);
}

.file-actions {
    display: flex;
    gap: 0.5rem;
}

.btn {
    display: inline-block;
    padding: 0.7rem 1.5rem;
    background-color: var(--pastel-blue);
    color: var(--white);
    border: none;
    border-radius: 30px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s ease;
    text-decoration: none;
    text-align: center;
    margin-top: 1rem;
}

.btn:hover {
    background-color: #8bc5d8;
    transform: translateY(-2px);
}

.btn-small {
    padding: 0.4rem 0.8rem;
    font-size: 0.9rem;
    margin-top: 0;
}

.download-btn {
    background-color: var(--pastel-green);
}

.download-btn:hover {
    background-color: #a8d89e;
}

footer {
    background-color: var(--pastel-blue);
    color: var(--white);
    text-align: center;
    padding: 2rem 1rem;
    margin-top: 3rem;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
}

.contact-info {
    margin-top: 1rem;
}

/* Modal pour afficher les présentations */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.7);
    z-index: 1000;
    align-items: center;
    justify-content: center;
}

.modal-content {
    background-color: var(--white);
    border-radius: 12px;
    width: 90%;
    max-width: 900px;
    max-height: 90vh;
    overflow: auto;
    padding: 2rem;
    position: relative;
}

.close-modal {
    position: absolute;
    top: 1rem;
    right: 1.5rem;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-light);
}

.close-modal:hover {
    color: var(--text-dark);
}

.modal-title {
    margin-bottom: 1rem;
    color: var(--pastel-blue);
}

.ppt-container {
    width: 100%;
    height: 500px;
    background-color: #f5f5f5;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 1rem 0;
    border: 1px dashed #ddd;
}

.ppt-placeholder {
    text-align: center;
    color: var(--text-light);
}

.ppt-placeholder i {
    font-size: 3rem;
    margin-bottom: 1rem;
    color: var(--pastel-blue);
}

/* Admin-specific styles */
.back-link {
    color: var(--white);
    text-decoration: none;
    font-size: 1rem;
    opacity: 0.9;
    transition: opacity 0.3s ease;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    border: 1px solid rgba(255,255,255,0.3);
    border-radius: 25px;
}

.back-link:hover {
    opacity: 1;
    background-color: rgba(255,255,255,0.1);
}

.stats-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--white);
    padding: 1.5rem;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 4px 12px var(--shadow);
}

.stat-number {
    font-size: 2.5rem;
    font-weight: bold;
    color: var(--pastel-blue);
    margin-bottom: 0.5rem;
}

.stat-label {
    color: var(--text-light);
    font-size: 0.9rem;
}

.btn-danger {
    background-color: #e74c3c;
}

.btn-danger:hover {
    background-color: #c0392b;
}

.btn-success {
    background-color: #2ecc71;
}

.btn-success:hover {
    background-color: #27ae60;
}

.btn-warning {
    background-color: var(--pastel-orange);
    color: var(--text-dark);
}

.btn-warning:hover {
    background-color: #ffc285;
}

.btn-info {
    background-color: var(--pastel-purple);
}

.btn-info:hover {
    background-color: #c5b0f9;
}

.admin-panel {
    background-color: var(--white);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 4px 12px var(--shadow);
    margin-bottom: 2rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--text-dark);
}

.form-control {
    width: 100%;
    padding: 0.8rem;
    border: 1px solid #ddd;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.form-control:focus {
    border-color: var(--pastel-blue);
    outline: none;
    box-shadow: 0 0 0 3px rgba(168, 216, 234, 0.2);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

.form-help {
    font-size: 0.85rem;
    color: var(--text-light);
    margin-top: 0.25rem;
}

.uploaded-files {
    margin-top: 2rem;
}

.files-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid #eee;
}

.search-box {
    padding: 0.5rem 1rem;
    border: 1px solid #ddd;
    border-radius: 25px;
    width: 300px;
}

.file-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem;
    border: 1px solid #eee;
    border-radius: 8px;
    margin-bottom: 1rem;
    transition: all 0.3s ease;
}

.file-item:hover {
    box-shadow: 0 4px 12px var(--shadow);
    transform: translateY(-2px);
}

.file-info {
    display: flex;
    align-items: center;
    flex: 1;
}

.file-icon-large {
    font-size: 2.5rem;
    color: var(--pastel-blue);
    margin-right: 1.5rem;
}

.file-details h4 {
    margin-bottom: 0.5rem;
    color: var(--text-dark);
}

.file-details p {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 0.25rem;
}

.file-meta {
    display: flex;
    gap: 1rem;
    margin-top: 0.5rem;
}

.file-meta span {
    background: #f5f5f5;
    padding: 0.25rem 0.75rem;
    border-radius: 15px;
    font-size: 0.8rem;
    color: var(--text-light);
}

.instructions {
    background-color: var(--pastel-orange);
    border-radius: 12px;
    padding: 2rem;
    margin-bottom: 2rem;
}

.instructions h3 {
    margin-bottom: 1rem;
    color: var(--text-dark);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.instructions ol {
    margin-left: 1.5rem;
}

.instructions li {
    margin-bottom: 0.75rem;
    line-height: 1.5;
}

.instructions strong {
    color: var(--text-dark);
}

.folder-structure {
    background: rgba(255,255,255,0.7);
    padding: 1.5rem;
    border-radius: 8px;
    margin-top: 1rem;
    font-family: monospace;
    line-height: 1.8;
}

.alert {
    padding: 1rem 1.5rem;
    border-radius: 8px;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.alert-success {
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.alert-warning {
    background-color: #fff3cd;
    color: #856404;
    border: 1px solid #ffeaa7;
}

.modal-actions {
    display: flex;
    gap: 1rem;
    justify-content: flex-end;
    margin-top: 1.5rem;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-container {
        flex-direction: column;
        align-items: center;
    }
    
    .nav-item {
        margin: 0.3rem 0;
        width: 80%;
        text-align: center;
    }
    
    .cards-container {
        grid-template-columns: 1fr;
    }
    
    .logo-container {
        flex-direction: column;
    }
    
    .logo {
        margin-right: 0;
        margin-bottom: 1rem;
    }
    
    .admin-link {
        position: static;
        margin-top: 1rem;
        display: block;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .file-item {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .file-actions {
        margin-top: 1rem;
        width: 100%;
        justify-content: flex-end;
    }
    
    .back-link {
        position: static;
        display: inline-flex;
        margin-bottom: 1rem;
    }
    
    .files-header {
        flex-direction: column;
        gap: 1rem;
        align-items: flex-start;
    }
    
    .search-box {
        width: 100%;
    }
    
    .stats-container {
        grid-template-columns: 1fr;
    }
}