:root {
    --primary-color: #c8102e;
    --secondary-color: #003b5c;
    --success-color: #28a745;
    --warning-color: #ffc107;
    --danger-color: #dc3545;
    --light-gray: #f8f9fa;
    --border-gray: #dee2e6;
    --text-dark: #212529;
    --text-muted: #6c757d;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--light-gray);
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 20px;
}

header {
    background: white;
    padding: 30px;
    border-radius: 8px;
    margin-bottom: 30px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    text-align: center;
}

.logo-container {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 30px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

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

h1 {
    color: var(--primary-color);
    font-size: 2rem;
    margin-bottom: 10px;
}

.subtitle {
    color: var(--text-muted);
    font-size: 1.1rem;
}

main {
    background: white;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.intro {
    margin-bottom: 30px;
    padding: 20px;
    background-color: var(--light-gray);
    border-radius: 6px;
    border-left: 4px solid var(--primary-color);
}

.classes-section {
    margin-bottom: 40px;
}

h2 {
    color: var(--secondary-color);
    font-size: 1.5rem;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--border-gray);
}

h3 {
    color: var(--secondary-color);
    font-size: 1.2rem;
    margin-top: 25px;
    margin-bottom: 10px;
}

.class-card {
    border: 1px solid var(--border-gray);
    border-radius: 6px;
    padding: 20px;
    margin-bottom: 15px;
    transition: box-shadow 0.3s ease;
}

.class-card:hover {
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.class-card.full {
    opacity: 0.6;
    background-color: #f5f5f5;
}

.class-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 15px;
    flex-wrap: wrap;
    gap: 10px;
}

.class-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-dark);
    flex: 1;
    min-width: 200px;
}

.class-date {
    font-size: 1rem;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    gap: 5px;
}

.class-description {
    color: var(--text-muted);
    margin-bottom: 15px;
}

.class-details {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    margin-bottom: 15px;
    font-size: 0.95rem;
}

.class-detail {
    display: flex;
    align-items: center;
    gap: 5px;
}

.class-detail strong {
    color: var(--secondary-color);
}

.class-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 10px;
}

.slots-available {
    font-weight: 600;
}

.slots-available.low {
    color: var(--warning-color);
}

.slots-available.full {
    color: var(--danger-color);
}

.slots-available.good {
    color: var(--success-color);
}

.btn-primary, .btn-secondary {
    padding: 10px 20px;
    border: none;
    border-radius: 4px;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 500;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
}

.btn-primary:hover:not(:disabled) {
    background-color: #a00d25;
}

.btn-primary:disabled {
    background-color: var(--border-gray);
    cursor: not-allowed;
}

.btn-secondary {
    background-color: white;
    color: var(--text-dark);
    border: 1px solid var(--border-gray);
}

.btn-secondary:hover {
    background-color: var(--light-gray);
}

.info-section {
    margin-top: 40px;
    padding-top: 30px;
    border-top: 2px solid var(--border-gray);
}

.info-section p {
    margin-bottom: 15px;
}

.info-section a {
    color: var(--primary-color);
    text-decoration: none;
}

.info-section a:hover {
    text-decoration: underline;
}

footer {
    text-align: center;
    padding: 20px;
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-top: 30px;
}

.loading {
    text-align: center;
    padding: 40px;
    color: var(--text-muted);
}

/* Modal Styles */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
    overflow-y: auto;
}

.modal.show {
    display: block;
}

.modal-content {
    background-color: white;
    margin: 50px auto;
    padding: 30px;
    border-radius: 8px;
    width: 90%;
    max-width: 500px;
    position: relative;
    box-shadow: 0 4px 20px rgba(0,0,0,0.3);
}

.close {
    position: absolute;
    right: 20px;
    top: 20px;
    font-size: 28px;
    font-weight: bold;
    color: var(--text-muted);
    cursor: pointer;
}

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

#modal-class-info {
    background-color: var(--light-gray);
    padding: 15px;
    border-radius: 6px;
    margin-bottom: 25px;
    border-left: 4px solid var(--primary-color);
}

#modal-class-info h3 {
    margin-top: 0;
    margin-bottom: 10px;
    color: var(--primary-color);
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    font-weight: 600;
    margin-bottom: 5px;
    color: var(--text-dark);
}

.form-group input {
    width: 100%;
    padding: 10px;
    border: 1px solid var(--border-gray);
    border-radius: 4px;
    font-size: 1rem;
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(200, 16, 46, 0.1);
}

.form-group small {
    display: block;
    margin-top: 5px;
    color: var(--text-muted);
    font-size: 0.875rem;
}

.form-actions {
    display: flex;
    gap: 10px;
    justify-content: flex-end;
    margin-top: 25px;
}

/* Admin Styles */
.admin-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    flex-wrap: wrap;
    gap: 15px;
}

.btn-logout {
    background-color: var(--danger-color);
    color: white;
}

.btn-logout:hover {
    background-color: #c82333;
}

.admin-tabs {
    display: flex;
    gap: 0;
    border-bottom: 2px solid var(--border-gray);
    margin-bottom: 30px;
}

.tab-btn {
    padding: 12px 24px;
    background: none;
    border: none;
    border-bottom: 3px solid transparent;
    cursor: pointer;
    font-size: 1rem;
    color: var(--text-muted);
    transition: all 0.3s ease;
}

.tab-btn.active {
    color: var(--primary-color);
    border-bottom-color: var(--primary-color);
}

.tab-btn:hover {
    color: var(--text-dark);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 20px;
}

table th {
    background-color: var(--secondary-color);
    color: white;
    padding: 12px;
    text-align: left;
    font-weight: 600;
}

table td {
    padding: 12px;
    border-bottom: 1px solid var(--border-gray);
}

table tr:hover {
    background-color: var(--light-gray);
}

.action-buttons {
    display: flex;
    gap: 5px;
}

.btn-small {
    padding: 5px 10px;
    font-size: 0.875rem;
}

.btn-danger {
    background-color: var(--danger-color);
    color: white;
}

.btn-danger:hover {
    background-color: #c82333;
}

.btn-success {
    background-color: var(--success-color);
    color: white;
}

.btn-success:hover {
    background-color: #218838;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    header, main {
        padding: 20px;
    }
    
    h1 {
        font-size: 1.5rem;
    }
    
    .logo {
        height: 60px;
    }
    
    .class-header {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .class-footer {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .modal-content {
        margin: 20px auto;
        width: 95%;
    }
    
    .form-actions {
        flex-direction: column;
    }
    
    .form-actions button {
        width: 100%;
    }
    
    table {
        font-size: 0.875rem;
    }
    
    .admin-tabs {
        overflow-x: auto;
    }
}