/* ========== 课程中心页面样式 ========== */

/* 主色调 - 橙色系 */
:root {
    --primary-color: #FF6B35;
    --primary-light: #FF8F66;
    --primary-gradient: linear-gradient(135deg, #FF6B35 0%, #FF8F66 100%);
    --text-dark: #333;
    --text-gray: #666;
    --text-light: #999;
    --bg-light: #f5f5f5;
    --border-color: #e8e8e8;
}

/* ========== 页面基础 ========== */
.courses-page {
    min-height: 100vh;
    background: var(--bg-light);
}

/* ========== 课程筛选区域 ========== */
.courses-filter {
    background: #fff;
    padding: 20px 0;
    border-bottom: 1px solid var(--border-color);
}

.filter-tabs {
    display: flex;
    gap: 10px;
    overflow-x: auto;
    padding-bottom: 4px;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
}

.filter-tabs::-webkit-scrollbar {
    display: none;
}

.filter-tab {
    flex-shrink: 0;
    padding: 10px 20px;
    font-size: 14px;
    color: var(--text-gray);
    background: #fff;
    border: 1px solid var(--border-color);
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    white-space: nowrap;
}

.filter-tab:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.filter-tab.active {
    background: var(--primary-gradient);
    border-color: var(--primary-color);
    color: #fff;
}

/* ========== 课程列表 ========== */
.courses-section {
    padding: 40px 0 60px;
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

/* ========== 课程卡片 ========== */
.course-card {
    background: #fff;
    border-radius: 16px;
    overflow: hidden;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.06);
    transition: all 0.3s ease;
    cursor: pointer;
    position: relative;
    border: 1px solid var(--border-color);
}

.course-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 12px 40px rgba(255, 107, 53, 0.15);
    border-color: var(--primary-light);
}

.course-card-image {
    position: relative;
    height: 180px;
    overflow: hidden;
    background: linear-gradient(135deg, #f3f4f6 0%, #e5e7eb 100%);
}

.course-card-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.4s ease;
}

.course-card:hover .course-card-image img {
    transform: scale(1.08);
}

.course-card-badge {
    position: absolute;
    top: 12px;
    left: 12px;
    padding: 6px 14px;
    font-size: 12px;
    font-weight: 600;
    color: #fff;
    border-radius: 20px;
    background: var(--primary-gradient);
    box-shadow: 0 2px 10px rgba(255, 107, 53, 0.4);
}

.course-card-duration {
    position: absolute;
    bottom: 12px;
    right: 12px;
    padding: 4px 10px;
    font-size: 12px;
    color: #fff;
    background: rgba(0, 0, 0, 0.6);
    border-radius: 12px;
    backdrop-filter: blur(4px);
}

.course-card-content {
    padding: 20px;
}

.course-card-title {
    font-size: 17px;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 10px;
    line-height: 1.4;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
    min-height: 48px;
}

.course-card-desc {
    font-size: 14px;
    color: var(--text-gray);
    line-height: 1.6;
    margin-bottom: 14px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.course-card-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 14px;
    border-top: 1px solid var(--border-color);
}

.course-card-teacher {
    display: flex;
    align-items: center;
    gap: 8px;
}

.course-card-avatar {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    object-fit: cover;
    background: var(--primary-gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 12px;
    font-weight: 600;
}

.course-card-avatar span {
    color: #fff;
}

.course-card-teacher span {
    font-size: 13px;
    color: var(--bg-light);
}

.course-card-price {
    font-size: 18px;
    font-weight: 700;
    color: var(--primary-color);
}

.course-card-price.free {
    color: #10B981;
}

/* ========== 空状态 ========== */
.no-data {
    text-align: center;
    padding: 80px 0;
    color: #999;
    grid-column: 1 / -1;
}

.no-data-icon {
    margin-bottom: 16px;
    opacity: 0.5;
}

/* ========== 加载状态 ========== */
.loading {
    text-align: center;
    padding: 60px 0;
    color: #999;
    grid-column: 1 / -1;
}

.loading::after {
    content: '';
    display: inline-block;
    width: 24px;
    height: 24px;
    margin-left: 8px;
    border: 3px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* ========== 分页样式 ========== */
.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 8px;
    margin-top: 40px;
    padding: 20px 0;
}

.pagination-btn {
    min-width: 40px;
    height: 40px;
    padding: 0 14px;
    font-size: 14px;
    color: var(--text-gray);
    background: #fff;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.pagination-btn:hover:not(.disabled):not(.active) {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.pagination-btn.active {
    background: var(--primary-gradient);
    border-color: var(--primary-color);
    color: #fff;
    box-shadow: 0 4px 15px rgba(255, 107, 53, 0.3);
}

.pagination-btn.disabled,
.pagination-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.pagination-btn.prev,
.pagination-btn.next {
    padding: 0 16px;
}

.pagination-ellipsis {
    padding: 0 8px;
    color: var(--text-light);
    font-size: 14px;
}

.pagination-info {
    margin-left: 16px;
    font-size: 14px;
    color: var(--text-light);
}

/* ========== 响应式适配 ========== */
@media screen and (max-width: 1200px) {
    .courses-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: 20px;
    }
}

@media screen and (max-width: 992px) {
    .courses-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 16px;
    }
}

@media screen and (max-width: 768px) {
    .courses-page {
        padding-top: 56px;
    }

    .courses-filter {
        padding: 12px 0;
    }

    .filter-tab {
        padding: 8px 14px;
        font-size: 13px;
    }

    .courses-section {
        padding: 24px 0 40px;
    }

    .courses-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
    }

    .course-card-image {
        height: 140px;
    }

    .course-card-content {
        padding: 14px;
    }

    .course-card-title {
        font-size: 15px;
        min-height: 42px;
        margin-bottom: 8px;
    }

    .course-card-desc {
        font-size: 12px;
        margin-bottom: 12px;
        -webkit-line-clamp: 2;
    }

    .course-card-meta {
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
        padding-top: 12px;
    }

    .course-card-price {
        font-size: 16px;
    }

    .pagination {
        margin-top: 30px;
    }

    .pagination-btn {
        min-width: 36px;
        height: 36px;
        font-size: 13px;
    }
}

@media screen and (max-width: 480px) {
    .courses-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
    }

    .course-card-image {
        height: 120px;
    }

    .course-card-content {
        padding: 12px;
    }

    .course-card-title {
        font-size: 14px;
        min-height: 40px;
        margin-bottom: 8px;
    }

    .course-card-desc {
        font-size: 12px;
        margin-bottom: 10px;
    }

    .course-card-meta {
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
        padding-top: 10px;
    }

    .filter-tabs {
        gap: 8px;
    }

    .filter-tab {
        padding: 6px 12px;
        font-size: 12px;
    }

    .pagination {
        gap: 4px;
    }

    .pagination-btn {
        min-width: 32px;
        height: 32px;
        padding: 0 10px;
        font-size: 12px;
    }

    .pagination-info {
        display: none;
    }
}