/* ========== 课程库页面 ========== */

.page-header {
    text-align: center;
    padding: 30px 20px 10px;
}
.page-header h1 {
    font-size: 28px;
    color: var(--primary);
    font-weight: 700;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}
.page-icon { font-size: 32px; }
.page-desc {
    font-size: 14px;
    color: var(--text-light);
    margin-bottom: 20px;
}

/* 筛选区 */
.course-filter {
    display: flex;
    flex-direction: column;
    gap: 16px;
}
.filter-search-row {
    display: flex;
    align-items: center;
    gap: 16px;
}
.filter-search {
    flex: 1;
    position: relative;
    display: flex;
    align-items: center;
}
.search-icon {
    position: absolute;
    left: 16px;
    color: var(--text-lighter);
    pointer-events: none;
}
.filter-search .filter-input {
    width: 100%;
    border: 2px solid var(--border);
    border-radius: 50px;
    padding: 12px 20px 12px 44px;
    font-size: 15px;
    outline: none;
    transition: border-color 0.2s;
    background: #fafafa;
}
.filter-search .filter-input:focus {
    border-color: var(--primary);
    background: #fff;
}
.filter-count {
    flex-shrink: 0;
    font-size: 13px;
    color: var(--text-lighter);
}
.filter-count strong {
    color: var(--primary);
    font-size: 18px;
    margin: 0 2px;
    font-weight: 700;
}

.filter-cats {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}
.cat-chip {
    padding: 6px 16px;
    border-radius: 20px;
    font-size: 13px;
    cursor: pointer;
    background: #f5f5f5;
    color: var(--text-light);
    transition: all 0.2s;
    border: 1px solid transparent;
    user-select: none;
}
.cat-chip:hover {
    background: var(--primary-light);
    color: var(--primary);
}
.cat-chip.active {
    background: var(--primary);
    color: #fff;
    border-color: var(--primary);
}

/* 排序 */
.filter-sort {
    display: flex;
    align-items: center;
    gap: 8px;
    padding-top: 4px;
    border-top: 1px solid var(--border);
}
.sort-label {
    font-size: 13px;
    color: var(--text-lighter);
}
.sort-btn {
    border: none;
    background: transparent;
    padding: 4px 12px;
    font-size: 13px;
    color: var(--text-light);
    cursor: pointer;
    border-radius: 6px;
    transition: all 0.2s;
}
.sort-btn:hover {
    background: var(--primary-light);
    color: var(--primary);
}
.sort-btn.active {
    background: var(--primary-light);
    color: var(--primary);
    font-weight: 600;
}

/* 课程列表 */
.course-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(360px, 1fr));
    gap: 16px;
    margin-bottom: 20px;
}
.course-card {
    background: #fff;
    border-radius: var(--radius);
    padding: 20px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
    transition: transform 0.2s, box-shadow 0.2s;
    position: relative;
}
.course-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(0,0,0,0.1);
}

/* 名师标识 */
.famous-badge {
    position: absolute;
    top: 16px;
    right: 16px;
    font-size: 11px;
    padding: 2px 8px;
    background: linear-gradient(135deg, #b8860b, #daa520);
    color: #fff;
    border-radius: 10px;
    font-weight: 500;
}

.course-category {
    display: inline-block;
    font-size: 12px;
    padding: 3px 10px;
    background: var(--primary-light);
    color: var(--primary);
    border-radius: 4px;
    margin-bottom: 10px;
    font-weight: 500;
}
.course-name {
    font-size: 17px;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 8px;
    line-height: 1.5;
    padding-right: 60px;
}
.course-desc {
    font-size: 13px;
    color: var(--text-light);
    margin-bottom: 12px;
    line-height: 1.6;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}
.course-meta {
    display: flex;
    align-items: center;
    gap: 12px;
    padding-top: 12px;
    border-top: 1px solid var(--border);
    font-size: 13px;
    color: var(--text-light);
}
.course-teacher {
    font-weight: 600;
    color: var(--text);
}
.course-duration {
    margin-left: auto;
    color: var(--secondary);
    font-weight: 500;
}
.course-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 4px;
    margin-bottom: 10px;
}
.course-tag {
    font-size: 11px;
    padding: 2px 8px;
    background: #f0f5ff;
    color: #1a56db;
    border-radius: 4px;
}

/* 空状态 */
.empty-state {
    grid-column: 1 / -1;
    text-align: center;
    padding: 60px 20px;
    color: var(--text-lighter);
    font-size: 14px;
}

/* 响应式 */
@media (max-width: 700px) {
    .course-list {
        grid-template-columns: 1fr;
    }
    .page-header h1 { font-size: 22px; }
    .filter-search-row {
        flex-direction: column;
        align-items: stretch;
        gap: 10px;
    }
    .filter-count { text-align: right; }
    .course-name { font-size: 15px; padding-right: 50px; }
}