/* 轮播图样式 */
.carousel-container {
    position: relative;
    width: 100%;
    height: 450px;
    overflow: hidden;
    margin-bottom: 3rem;
}

.carousel {
    position: relative;
    width: 100%;
    height: 100%;
}

.carousel-slide {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0;
    transition: opacity 1s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.carousel-slide.active {
    opacity: 1;
}

.carousel-slide-content {
    position: relative;
    z-index: 2;
    text-align: center;
    color: white;
    max-width: 900px;
    padding: 2rem;
    width: 100%;
}

.carousel-slide-title {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 1.2rem;
    line-height: 1.2;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

.carousel-slide-subtitle {
    font-size: 1.3rem;
    margin-bottom: 2.2rem;
    font-weight: 300;
    opacity: 0.95;
    text-shadow: 0 1px 5px rgba(0, 0, 0, 0.3);
}

.carousel-slide-buttons {
    display: flex;
    gap: 1.5rem;
    justify-content: center;
}

.carousel-slide-buttons .btn {
    min-width: 160px;
}

/* 轮播图背景容器 */
.slide-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
    overflow: hidden;
}

/* 背景图片样式 */
.slide-bg img {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center;
    transition: transform 0.5s ease;
}

/* 鼠标悬停时图片放大效果 */
.carousel-slide:hover .slide-bg img {
    transform: scale(1.05);
}

/* 渐变覆盖层 */
.slide-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 2;
}

/* 蓝色渐变 */
.gradient-blue {
    background: linear-gradient(rgba(5, 60, 162, 0.7), rgba(5, 60, 162, 0.85));
}

/* 深蓝色渐变 */
.gradient-blue-dark {
    background: linear-gradient(rgba(0, 102, 153, 0.7), rgba(0, 51, 102, 0.85));
}

/* 更深蓝色渐变 */
.gradient-blue-darker {
    background: linear-gradient(rgba(0, 51, 102, 0.7), rgba(0, 26, 77, 0.85));
}

/* 内容层（在渐变层上方） */
.carousel-slide-content {
    position: relative;
    z-index: 3;
    color: white;
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 轮播图指示器 */
.carousel-indicators {
    position: absolute;
    bottom: 2rem;
    left: 0;
    width: 100%;
    display: flex;
    justify-content: center;
    gap: 0.8rem;
    z-index: 3;
}

.carousel-indicator {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background-color: rgba(255, 255, 255, 0.5);
    cursor: pointer;
    transition: var(--transition);
}

.carousel-indicator.active {
    background-color: white;
    transform: scale(1.2);
}

/* 轮播图控制按钮 */
.carousel-controls {
    position: absolute;
    top: 50%;
    width: 100%;
    display: flex;
    justify-content: space-between;
    padding: 0 2rem;
    transform: translateY(-50%);
    z-index: 3;
}

.carousel-control {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background-color: rgba(255, 255, 255, 0.2);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    cursor: pointer;
    transition: var(--transition);
    border: none;
}

.carousel-control:hover {
    background-color: rgba(255, 255, 255, 0.3);
    transform: scale(1.1);
}


/* 新闻板块 */
.news-main-section {
    padding: 3rem 0;
    background-color: var(--light-gray);
}

.news-main-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(500px, 1fr));
    gap: 2.5rem;
}

.news-main-column {
    background-color: white;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.news-main-column:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
}

.news-main-header {
    background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 1.5rem;
}

.news-main-title {
    font-size: 1.4rem;
    font-weight: 600;
}

.news-main-list {
    padding: 1.5rem;
}

.news-main-item {
    padding: 1rem 0;
    border-bottom: 1px solid var(--border-color);
}

.news-main-item:last-child {
    border-bottom: none;
}

.news-main-link {
    display: block;
    color: var(--dark-color);
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.news-main-link:hover {
    color: var(--primary-color);
}

.news-main-date {
    font-size: 0.85rem;
    color: var(--medium-gray);
}

.view-all {
    display: inline-block;
    margin-top: 1rem;
    color: var(--secondary-color);
    font-weight: 600;
}

.view-all:hover {
    color: var(--primary-color);
}

/* 课程列表部分 */
.course-list-section {
    padding: 3rem 0;
    background-color: var(--light-gray);
}

.course-list-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    justify-content: start;
}
/* 当屏幕宽度足够时，强制2列平分 */
@media (min-width: 600px) {
    .course-list-grid {
        grid-template-columns: 1fr 1fr;
    }
}

.course-list-item {
    background-color: white;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
    /* max-width: 50%; */
}

.course-list-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
}

.course-list-image {
    height: 180px;
    background-color: var(--primary-light);
    background-size: cover;
    background-position: center;
}

.course-list-content {
    padding: 1.5rem;
}

.course-list-title {
    font-size: 1.3rem;
    color: var(--primary-color);
    margin-bottom: 0.8rem;
}

.course-list-meta {
    display: flex;
    justify-content: space-between;
    margin-bottom: 1rem;
}

.course-list-date,
.course-list-category {
    font-size: 0.85rem;
    color: var(--medium-gray);
}

.course-list-content p {
    color: var(--medium-gray);
    margin-bottom: 1.2rem;
}

/* 往期回顾部分 */
.past-review-section {
    padding: 3rem 0;
}

.past-review-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2.5rem;
    justify-content: start;
}
/* 当屏幕宽度足够时，强制2列平分 */
@media (min-width: 600px) {
    .past-review-container {
        grid-template-columns: 1fr 1fr;
    }
}

.past-review-item {
    background-color: white;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.past-review-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
}

.past-review-image {
    height: 250px;
    background-color: var(--primary-light);
    background-size: cover;
    background-position: center;
}

.past-review-content {
    padding: 1.5rem;
}

.past-review-title {
    font-size: 1.4rem;
    color: var(--primary-color);
    margin-bottom: 0.8rem;
}

.past-review-meta {
    display: flex;
    justify-content: space-between;
    margin-bottom: 1rem;
}

.past-review-date,
.past-review-author {
    font-size: 0.85rem;
    color: var(--medium-gray);
}

.past-review-content p {
    color: var(--medium-gray);
    margin-bottom: 1.2rem;
}

/* 在线视频部分 */
.video-section {
    padding: 3rem 0;
    background-color: var(--light-gray);
}

.video-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    justify-content: start;
}
/* 当屏幕宽度足够时，强制2列平分 */
@media (min-width: 600px) {
    .video-grid {
        grid-template-columns: 1fr 1fr;
    }
}


.video-item {
    background-color: white;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.video-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
}

.video-thumbnail {
    height: 180px;
    background-color: var(--primary-light);
    background-size: cover;
    background-position: center;
    position: relative;
}

.video-play-btn {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 60px;
    height: 60px;
    background-color: rgba(0, 0, 0, 0.7);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
}

.video-content {
    padding: 1.5rem;
}

.video-title {
    font-size: 1.2rem;
    color: var(--primary-color);
    margin-bottom: 0.8rem;
}

.video-meta {
    display: flex;
    justify-content: space-between;
    margin-bottom: 1rem;
}

.video-duration,
.video-views {
    font-size: 0.85rem;
    color: var(--medium-gray);
}

.video-content p {
    color: var(--medium-gray);
    margin-bottom: 1.2rem;
}

.video-link {
    display: block;           /* 让 a 标签充满容器 */
    text-decoration: none;     /* 去掉下划线 */
    color: inherit;           /* 继承文字颜色 */
    border: none;            /* 去掉链接边框（可选） */
    cursor: pointer;         /* 鼠标手型 */
    outline: none;           /* 可访问性：可保留焦点边框 */
    border-radius: 8px;      /* 可选，与封面圆角一致 */
    overflow: hidden;        /* 可选，确保封面图圆角生效 */
}

/* 学术文章部分 */
.articles-section {
    padding: 3rem 0;
}


.articles-grid {
    display: grid;
    /* 默认情况（手机端）：1列 */
    grid-template-columns: 1fr; 
    gap: 2rem; /* 建议稍微减小间距，让手机端更好看 */
    justify-content: start;
}

/* 平板 (768px - 992px)：显示 2 列 */
@media (min-width: 768px) and (max-width: 992px) {
    .articles-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* 电脑 (大于 992px)：显示 3 列 */
@media (min-width: 993px) {
    .articles-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.article-item {
    background-color: white;
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.article-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
}

.article-category {
    display: inline-block;
    background-color: var(--light-gray);
    color: var(--primary-color);
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.article-title {
    font-size: 1.3rem;
    color: var(--primary-color);
    margin-bottom: 0.8rem;
}

.article-meta {
    display: flex;
    justify-content: space-between;
    margin-bottom: 1rem;
}

.article-date,
.article-author {
    font-size: 0.85rem;
    color: var(--medium-gray);
}

.article-item p {
    color: var(--medium-gray);
    margin-bottom: 1.2rem;
}


/* 会员与认证部分 */
.membership-section {
    padding: 3rem 0;
    background-color: var(--light-gray);
}

.membership-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2.5rem;
}

.membership-card {
    background-color: white;
    border-radius: var(--border-radius);
    padding: 2.5rem 2rem;
    box-shadow: var(--shadow);
    text-align: center;
    transition: var(--transition);
}

.membership-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
}

.membership-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
    color: white;
    font-size: 2rem;
}

.membership-card h3 {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.membership-card p {
    color: var(--medium-gray);
    margin-bottom: 1.5rem;
}

.process-steps {
    margin-top: 1.5rem;
    text-align: left;
}

.process-step {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1rem;
    padding-bottom: 1rem;
    border-bottom: 1px dashed var(--border-color);
}

.process-step:last-child {
    border-bottom: none;
}

.step-number {
    width: 30px;
    height: 30px;
    background-color: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 0.9rem;
}

/* 响应式设计 - 移动端适配 */
@media (max-width: 1100px) {
    .news-main-grid {
        grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    }

    .past-review-container {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 992px) {
    .carousel-slide-title {
        font-size: 2.5rem;
    }
}

/* 响应式设计 - 移动端适配 */
@media (max-width: 768px) {
    .carousel-container {
        height: 400px;
    }

    .carousel-slide-title {
        font-size: 2.2rem;
    }

    .carousel-slide-subtitle {
        font-size: 1.1rem;
    }

    .carousel-slide-buttons {
        flex-direction: column;
        align-items: center;
    }

    .carousel-slide-buttons .btn {
        width: 100%;
        max-width: 300px;
    }

    .carousel-controls {
        padding: 0 1rem;
    }

    .carousel-control {
        width: 40px;
        height: 40px;
        font-size: 1.2rem;
    }

    .news-main-grid {
        grid-template-columns: 1fr;
    }

    .past-review-container {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 576px) {
    .carousel-container {
        height: 350px;
    }

    .carousel-slide-title {
        font-size: 1.8rem;
    }

    .carousel-slide-subtitle {
        font-size: 0.95rem;
    }

    .section-title {
        font-size: 1.5rem;
    }

    .footer-content {
        grid-template-columns: 1fr;
    }

    .search-box input {
        width: 120px;
    }

    .search-box input:focus {
        width: 150px;
    }
}