/* 共享板块样式 */
.content-section {
    position: relative;
    padding: 40px 0;
    background-color: #d8e5fa;
}

/* 左右背景色延伸 */
.content-section::before,
.content-section::after {
    content: '';
    position: absolute;
    top: 0;
    width: 100vw;
    height: 100%;
    background-color: inherit;
    z-index: -1;
}

.content-section::before {
    right: 100%;
}

.content-section::after {
    left: 100%;
}

/* 内容容器 */
.section-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 标题样式 */
.section-header {
    margin-bottom: 40px;
    position: relative;
}

.section-title {
    font-size: 2.2rem;
    color: #000;
    font-weight: 600;
    display: inline-block;
    margin-bottom: 8px;
}

/* 增强的下划线 */
.section-underline {
    height: 3px;
    background: #e0e0e0;
    position: relative;
}

.section-underline::after {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 70px;
    height: 100%;
    background: #555;
}

/* 分类按钮组 */
.department-filter {
    display: inline-flex;
    gap: 20px;
    position: relative;
    padding: 10px 25px;
    border-radius: 30px;
}

.filter-btn {
    background: none;
    border: none;
    padding: 5px 0;
    font-size: 16px;
    color: #666;
    cursor: pointer;
    position: relative;
}

.filter-btn.active {
    color: #000;
    font-weight: 600;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .section-header {
        padding-bottom: 50px;
    }

    .section-title {
        position: static;
        text-align: center;
        margin-bottom: 15px !important;
    }

    .department-wrapper {
        position: absolute;
        bottom: 15px;
        left: 0;
        right: 0;
    }

    .department-filter {
        flex-wrap: wrap;
        justify-content: center;
        padding: 8px 15px;
        gap: 12px;
    }
}

@media (max-width: 480px) {
    .filter-btn {
        font-size: 0.9rem;
        padding: 6px 12px;
    }
}

/* 课程网格 */
.courses-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 25px;
    position: relative;
}

/* 课程项 */
.course-item {
    display: flex;
    align-items: center;
    padding: 15px 0;
    transition: all 0.3s ease;
    will-change: transform, opacity;
}

.course-item.hidden {
    display: none; /* 改为完全隐藏而不是保留空间 */
}

.course-item:hover {
    transform: translateY(-3px);
}

.course-icon {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    margin-right: 15px;
    object-fit: cover;
}

.course-info {
    flex: 1;
}

.course-title {
    font-size: 1.3rem;
    color: #000;
    font-weight: 600;
    margin-bottom: 5px;
}

.course-category {
    font-size: 0.7rem;
    color: #666;
}


/* 响应式设计 */
@media (max-width: 768px) {
    .expert-row {
        flex-direction: column;
        gap: 20px;
        padding: 20px 0;
    }

    .expert-avatar {
        align-self: center;
    }

    .expert-info {
        text-align: center;
    }
}