/* 页面头部 */
.header-block {
    margin-bottom: 26px;
}

.header-block h1 {
    font-size: 32px;
    font-weight: 600;
    margin-bottom: 8px;
}

.header-block p {
    font-size: 16px;
    color: #595e69;
}

/* 主体容器 左右布局 */
.main-wrap {
    display: flex;
    gap: 20px;
}

/* 左侧分类栏 */
.sidebar-cate {
    width: 210px;
    background: #ffffff;
    border-radius: 10px;
    padding: 20px;
    box-shadow: 0 1px 6px rgba(0, 0, 0, 0.06);
    flex-shrink: 0;
}

.sidebar-cate .title {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 20px;
    font-weight: 500;
    margin-bottom: 18px;
}

.cate-list .cate-item {
    padding: 10px 14px;
    border: 1px solid #e4e7ed;
    border-radius: 6px;
    margin-bottom: 10px;
    cursor: pointer;
    transition: all 0.2s ease;
    font-size: 20px;
    font-weight: 500;
}

.cate-list .cate-item:hover {
    border-color: #2577f3;
    background-color: #ecf4ff;
}

.cate-list .cate-item.active {
    border-color: #2577f3;
    background-color: #ecf4ff;
    color: #2577f3;
}

/* 右侧内容区域 */
.content-right {
    flex: 1;
    background: #ffffff;
    border-radius: 10px;
    padding: 24px;
    box-shadow: 0 1px 6px rgba(0, 0, 0, 0.06);
}

.content-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 22px;
}

.content-top h2 {
    font-size: 22px;
    font-weight: 600;
}

.btn-blue {
    background-color: #2577f3;
    color: #fff;
    border: none;
    border-radius: 6px;
    padding: 10px 28px;
    font-size: 15px;
    cursor: pointer;
}

/* 课程卡片网格 */
.course-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    margin-bottom: 30px;
}

.course-card {
    border-radius: 8px;
    overflow: hidden;
    border: 1px solid #eeeeee;
    transition: 0.24s;
}

.course-card:hover {
    box-shadow: 0 5px 16px rgba(0, 0, 0, 0.1);
}

.card-preview {
    position: relative;
    width: 100%;
    height: 176px;
    background-color: #dce7f5;
}

.play-circle {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    width: 48px;
    height: 48px;
    background: rgba(255, 255, 255, 0.82);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
}

.card-body {
    padding: 13px;
}

.card-name {
    font-size: 20px;
    margin-bottom: 8px;
}

.card-footer {
    display: flex;
    justify-content: space-between;
    font-size: 15px;
    color: #747985;
}

/* 分页 */
.page-box {
    display: flex;
    justify-content: flex-end;
    align-items: center;
    gap: 6px;
}

.page-box button {
    padding: 6px 12px;
    border: 1px solid #ddd;
    background: #fff;
    border-radius: 4px;
    cursor: pointer;
}

.page-box button.active {
    background: #2577f3;
    color: #fff;
    border-color: #2577f3;
}

.img-box {
    width: 100%;
    height: 160px;
    background: #FFF;
    display: flex;
    align-items: center;    /* 垂直居中 */
    justify-content: center;/* 水平居中 */
}
.img-box img {
    width: 100%;
    height: 100%;
    object-fit: contain; /* 核心！保持原图比例，不会拉伸变形，多余区域显示容器底色 */
}