/* Общие стили */
:root {
    --primary-color: #3498db;
    --secondary-color: #2c3e50;
    --success-color: #27ae60;
    --danger-color: #e74c3c;
    --warning-color: #f39c12;
    --light-color: #ecf0f1;
    --dark-color: #34495e;
    --border-radius: 8px;
    --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8f9fa;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Навигация */
.navbar {
    background-color: var(--secondary-color);
    color: white;
    padding: 1rem 0;
    box-shadow: var(--box-shadow);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-links {
    display: flex;
    list-style: none;
}

.nav-links li {
    margin-left: 1.5rem;
}

.nav-links a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
}

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

.brand {
    font-size: 1.5rem;
    font-weight: bold;
}

/* Кнопки */
.btn {
    display: inline-block;
    background-color: var(--primary-color);
    color: white;
    padding: 0.6rem 1.2rem;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    text-decoration: none;
    text-align: center;
    transition: var(--transition);
}

.btn:hover {
    background-color: #2980b9;
    transform: translateY(-2px);
}

.btn-sm {
    padding: 0.4rem 0.8rem;
    font-size: 0.9rem;
}

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

.btn-success:hover {
    background-color: #219653;
}

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

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

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

.btn-warning:hover {
    background-color: #d35400;
}

.btn-outline {
    background-color: transparent;
    border: 1px solid var(--primary-color);
    color: var(--primary-color);
}

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

/* Формы */
.form-container {
    max-width: 800px;
    margin: 2rem auto;
    padding: 2rem;
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
}

.form-header {
    margin-bottom: 1.5rem;
    text-align: center;
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.form-control {
    width: 100%;
    padding: 0.8rem;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
}

.form-control:focus {
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.2);
}

.form-actions {
    margin-top: 1.5rem;
    display: flex;
    gap: 1rem;
}

/* Карточки */
.card {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    overflow: hidden;
    margin-bottom: 1.5rem;
    transition: var(--transition);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}

.card-header {
    padding: 1.2rem;
    background-color: var(--light-color);
    border-bottom: 1px solid #ddd;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.card-body {
    padding: 1.5rem;
}

.card-footer {
    padding: 1rem;
    background-color: #f8f9fa;
    border-top: 1px solid #ddd;
    display: flex;
    justify-content: flex-end;
    gap: 0.8rem;
}

/* Таблицы */
.table-container {
    overflow-x: auto;
    margin: 1.5rem 0;
}

table {
    width: 100%;
    border-collapse: collapse;
    background: white;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--box-shadow);
}

th, td {
    padding: 1rem;
    text-align: left;
    border-bottom: 1px solid #eee;
}

th {
    background-color: var(--secondary-color);
    color: white;
    font-weight: 600;
}

tr:nth-child(even) {
    background-color: #f9f9f9;
}

tr:hover {
    background-color: #f1f1f1;
}

/* Сообщения */
.alert {
    padding: 1rem;
    margin: 1rem 0;
    border-radius: var(--border-radius);
    position: relative;
    display: flex;
    align-items: center;
}

.alert-success {
    background-color: #d4edda;
    color: #155724;
    border-left: 4px solid var(--success-color);
}

.alert-error {
    background-color: #f8d7da;
    color: #721c24;
    border-left: 4px solid var(--danger-color);
}

.alert-info {
    background-color: #d1ecf1;
    color: #0c5460;
    border-left: 4px solid var(--primary-color);
}

.alert-warning {
    background-color: #fff3cd;
    color: #856404;
    border-left: 4px solid var(--warning-color);
}

.alert .close {
    margin-left: auto;
    cursor: pointer;
    font-weight: bold;
    font-size: 1.2rem;
}

/* Статусные бейджи */
.status-badge {
    display: inline-block;
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
}

.status-new {
    background-color: #d4edda;
    color: #155724;
}

.status-processing {
    background-color: #fff3cd;
    color: #856404;
}

.status-completed {
    background-color: #cce5ff;
    color: #004085;
}

/* Разделители */
.section {
    margin: 2rem 0;
    padding: 1.5rem;
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
}

.section-header {
    margin-bottom: 1.5rem;
    padding-bottom: 0.8rem;
    border-bottom: 1px solid #eee;
}

/* Утилиты */
.text-center {
    text-align: center;
}

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }

.flex {
    display: flex;
}

.flex-between {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.gap-1 { gap: 0.5rem; }
.gap-2 { gap: 1rem; }
.gap-3 { gap: 1.5rem; }

/* Адаптивность */
@media (max-width: 768px) {
    .navbar .container {
        flex-direction: column;
    }
    
    .nav-links {
        margin-top: 1rem;
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .nav-links li {
        margin: 0.5rem;
    }
    
    .form-container {
        padding: 1.5rem;
    }
    
    .card-footer {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
        margin-bottom: 0.5rem;
    }
}

/* Дополнительные стили для управления классами */
.class-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1.5rem;
}

.student-card {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 1.2rem;
    transition: var(--transition);
}

.student-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}