/* 课程页面特定样式 */

/* 页面标题 */
.page-header {
    background: linear-gradient(135deg, #3b7dd8, #2a5f9e);
    color: #fff;
    padding: 56px 0 40px 0;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.page-header h1 {
    color: #fff;
    font-size: 2.4rem;
    font-weight: bold;
    margin-bottom: 12px;
}

.page-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url("data:image/svg+xml,%3Csvg width='20' height='20' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M0 0h20v20H0z' fill='%23ffffff' fill-opacity='0.05'/%3E%3C/svg%3E");
    opacity: 0.3;
}

.page-header::after {
    content: '';
    position: absolute;
    top: 20%;
    right: -100px;
    width: 200px;
    height: 200px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(255,255,255,0.15) 0%, rgba(255,255,255,0) 70%);
    animation: float 6s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0px) scale(1); }
    50% { transform: translateY(-20px) scale(1.05); }
}

.page-header h1 {
    position: relative;
    z-index: 1;
}

.page-header p {
    color: rgba(255, 255, 255, 0.9);
    font-size: 1.1rem;
    margin: 0;
    position: relative;
    z-index: 1;
}

/* 课程筛选 */
.course-filter {
    background: #f8f9fa;
    padding: 30px 0;
    margin-bottom: 40px;
}

.filter-options {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.filter-group {
    width: 100%;
}

.filter-group h3 {
    margin-bottom: 15px;
    color: #333;
    font-size: 1.1rem;
}

.filter-items {
    display: flex;
    flex-wrap: nowrap;
    gap: 10px;
    overflow-x: auto;
    padding-bottom: 5px;
    scrollbar-width: thin;
}

.filter-items::-webkit-scrollbar {
    height: 4px;
}

.filter-items::-webkit-scrollbar-thumb {
    background-color: #ccc;
    border-radius: 4px;
}

.filter-item {
    padding: 8px 16px;
    background: #fff;
    border-radius: 20px;
    color: #666;
    text-decoration: none;
    font-size: 0.95rem;
    transition: all 0.3s ease;
    border: 1px solid #e0e0e0;
    white-space: nowrap;
}

.filter-item:hover,
.filter-item.active {
    background: #4a90e2;
    color: #fff;
    border-color: #4a90e2;
}

.search-box {
    display: flex;
    gap: 10px;
    max-width: 500px;
}

.search-box input {
    flex: 1;
    padding: 12px 15px;
    border: 1px solid #e1e8ed;
    border-radius: 4px;
    font-size: 1rem;
}

.search-box button {
    background-color: #3498db;
    color: white;
    border: none;
    border-radius: 4px;
    padding: 0 15px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* 课程部分 */
.courses-section {
    padding: 40px 0;
}

.section-title {
    font-size: 2rem;
    margin-bottom: 40px;
    color: #2c3e50;
    text-align: center;
    position: relative;
}

.section-title:after {
    content: '';
    display: block;
    width: 80px;
    height: 4px;
    background-color: #3498db;
    margin: 15px auto 0;
    border-radius: 2px;
}

.section-desc {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 40px;
    color: #666;
    font-size: 1.1rem;
    line-height: 1.6;
}

/* 单元样式 */
.unit-section {
    margin-bottom: 50px;
}

.unit-title {
    font-size: 1.5rem;
    color: #333;
    margin-bottom: 30px;
    padding-bottom: 15px;
    border-bottom: 2px solid #f0f0f0;
    position: relative;
}

.unit-title::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 60px;
    height: 2px;
    background: #4a90e2;
}

/* 课程卡片样式 */
.course-card {
    background: #fff;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    display: flex;
    flex-direction: column;
    height: 100%;
    margin-bottom: 30px;
}

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

.course-image {
    position: relative;
    width: 100%;
    padding-top: 56.25%; /* 16:9 宽高比 */
    overflow: hidden;
}

.course-image img {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.course-card:hover .course-image img {
    transform: scale(1.05);
}

.course-tag {
    position: absolute;
    top: 15px;
    right: 15px;
    background: rgba(255, 255, 255, 0.9);
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
    color: #333;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.course-content {
    padding: 20px;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.course-content h3 {
    margin: 0 0 12px;
    font-size: 1.2rem;
    color: #333;
    line-height: 1.4;
}

.course-content p {
    margin: 0 0 15px;
    color: #666;
    font-size: 0.95rem;
    line-height: 1.5;
    flex: 1;
}

.course-meta {
    display: flex;
    justify-content: space-between;
    color: #888;
    font-size: 0.9rem;
    margin-bottom: 15px;
}

.course-meta span {
    display: flex;
    align-items: center;
    gap: 5px;
}

.course-meta img {
    opacity: 0.7;
}

/* 即将推出区域 */
.coming-soon {
    background-color: #f5f9fc;
    padding: 60px 0;
    text-align: center;
    margin-bottom: 40px;
}

.subscribe-form {
    max-width: 600px;
    margin: 0 auto;
    display: flex;
    gap: 15px;
}

.subscribe-form input {
    flex: 1;
    padding: 12px 20px;
    border: 1px solid #e1e8ed;
    border-radius: 4px;
    font-size: 1rem;
}

.subscribe-form .btn {
    padding: 12px 25px;
    font-weight: 500;
}

/* 分页 */
.pagination {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin-top: 40px;
}

.pagination a {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: 1px solid #e1e8ed;
    color: #666;
    text-decoration: none;
    transition: all 0.3s ease;
}

.pagination a.active {
    background-color: #3498db;
    color: white;
    border-color: #3498db;
}

.pagination a:hover {
    background-color: #f0f7ff;
    border-color: #3498db;
}

.pagination a.next {
    width: auto;
    padding: 0 15px;
    border-radius: 20px;
}

/* 响应式调整 */
@media (max-width: 768px) {
    .courses-grid {
        grid-template-columns: 1fr;
    }
    
    .filter-options {
        flex-direction: column;
    }
    
    .filter-group {
        width: 100%;
    }
    
    .search-box {
        max-width: 100%;
    }
    
    .subscribe-form {
        flex-direction: column;
    }
}