/* 首页样式 */
.index-container {
    padding: 40px 0;
}

.page-header {
    text-align: center;
    margin-bottom: 50px;
}

.page-title {
    font-size: 36px;
    font-weight: 700;
    color: #333;
    margin-bottom: 15px;
}

.page-subtitle {
    font-size: 16px;
    color: #666;
    max-width: 600px;
    margin: 0 auto;
}

/* 课件卡片网格 */
.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 30px;
    margin-bottom: 40px;
}

.course-card {
    background: white;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    transition: transform 0.3s, box-shadow 0.3s;
    cursor: pointer;
}

.course-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 24px rgba(0,0,0,0.15);
}

.course-card-header {
    padding: 40px 20px;
    color: white;
    text-align: center;
    min-height: 150px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.course-card-title {
    font-size: 28px;
    font-weight: 700;
    margin: 0;
    color: white;
}

.course-card-body {
    padding: 25px;
}

.course-card-description {
    color: #666;
    margin-bottom: 15px;
    font-size: 14px;
    line-height: 1.6;
}

.course-card-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 20px;
}

.badge {
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 12px;
    font-weight: 500;
}

.badge-free {
    background-color: #d4edda;
    color: #155724;
}

.badge-price {
    background-color: #fff3cd;
    color: #856404;
}

.badge-category {
    background-color: #d1ecf1;
    color: #0c5460;
}

.badge-subcategory {
    background-color: #e2e3e5;
    color: #383d41;
}

.btn-view {
    width: 100%;
    text-align: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 12px;
    border-radius: 6px;
    text-decoration: none;
    display: block;
    transition: all 0.3s;
}

.btn-view:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: #999;
    grid-column: 1 / -1;
}

/* 筛选区域 */
.filter-section {
    margin-bottom: 30px;
    padding: 20px;
    background: white;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.filter-buttons {
    display: flex;
    gap: 15px;
    margin-bottom: 15px;
}

.filter-btn,
.sub-filter-btn {
    padding: 10px 20px;
    border-radius: 6px;
    text-decoration: none;
    color: #666;
    background: #f5f7fa;
    transition: all 0.3s;
}

.filter-btn:hover,
.sub-filter-btn:hover,
.filter-btn.active,
.sub-filter-btn.active {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.sub-filter-buttons {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

/* 分页 */
.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 15px;
    margin-top: 40px;
    padding: 20px;
}

.page-link {
    padding: 10px 20px;
    background: white;
    border-radius: 6px;
    text-decoration: none;
    color: #667eea;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    transition: all 0.3s;
}

.page-link:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.3);
}

.page-info {
    color: #666;
    font-size: 14px;
}

.login-prompt {
    text-align: center;
    padding: 40px;
    background: white;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    margin-top: 40px;
}

.login-prompt p {
    margin-bottom: 20px;
    color: #666;
    font-size: 16px;
}

/* 响应式 */
@media (max-width: 768px) {
    .courses-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .page-title {
        font-size: 28px;
    }
}