/* 仅作用于特定作用域，避免影响全局 Header 和 Footer */
.research-news-page {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    color: #333;
    max-width: 1440px;
    margin: 0 auto;
    padding: 60px 0;
    box-sizing: border-box;
    background-color: #fff;
}

.research-news-page * {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

.research-news-page a {
    text-decoration: none;
}

/* --- 页面整体布局 --- */
.research-news-page .rn-container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 40px;
    display: grid;
    grid-template-columns: 220px 1fr;
    column-gap: 70px;
}

/* --- 左侧标题区域 --- */
.research-news-page .rn-page-title {
    font-size: 34px;
    font-weight: 600;
    color: #222;
    position: relative;
    padding-left: 20px;
    padding-bottom: 20px;
    margin-bottom: 30px;
    border-bottom: 1px solid #eeeeee;
    line-height: 1.2;
}

.research-news-page .rn-page-title::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(calc(-50% - 10px));
    width: 4px;
    height: 50px;
    background-color: #6f2c91;
}

/* --- 左侧分类导航 --- */
.research-news-page .rn-cat-title {
    font-size: 24px;
    font-weight: 600;
    color: #222;
    margin-bottom: 25px;
}

.research-news-page .rn-cat-list {
    display: flex;
    flex-direction: column;
    gap: 25px;
}

.research-news-page .rn-cat-item {
    font-size: 16px;
    color: #333;
    position: relative;
    padding-left: 18px;
    transition: color 0.3s ease;
    line-height: 1.5;
}

.research-news-page .rn-cat-item:hover {
    color: #6f2c91;
}

.research-news-page .rn-cat-item.active {
    color: #6f2c91;
    font-weight: 600;
}

.research-news-page .rn-cat-item.active::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 3px;
    height: 18px;
    background-color: #6f2c91;
}

/* --- 右侧新闻区域 --- */
.research-news-page .rn-news-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 45px 24px;
}

/* --- 新闻卡片设计 --- */
.research-news-page .rn-news-card {
    display: flex;
    flex-direction: column;
    background-color: #fff;
    border: 1px solid #e5e5e5;
    transition: all 0.3s ease;
    overflow: hidden;
}

/* 卡片图片 */
.research-news-page .rn-card-image {
    width: 100%;
    aspect-ratio: 4 / 3;
    overflow: hidden;
}

.research-news-page .rn-card-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
    display: block;
}

/* 卡片文字区域 */
.research-news-page .rn-card-text {
    padding: 20px 20px 22px;
    position: relative;
    flex: 1;
    display: flex;
    flex-direction: column;
}

/* 日期样式 */
.research-news-page .rn-card-date {
    font-size: 15px;
    color: #8a8a8a;
    margin-bottom: 14px;
}

/* 新闻标题 */
.research-news-page .rn-card-title {
    /*font-size: 17px;*/
    /*line-height: 1.8;*/
    font-size: 16px;
    line-height: 4;
    color: #333;
    font-weight: 400;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
    transition: color 0.3s ease;
}

/* 右箭头 */
.research-news-page .rn-card-arrow {
    position: absolute;
    right: 20px;
    bottom: 20px;
    color: #6f2c91;
    font-size: 18px;
    transition: transform 0.3s ease;
    font-family: Arial, sans-serif;
}

/* --- Hover 效果 --- */
.research-news-page .rn-news-card:hover .rn-card-image img {
    transform: scale(1.03);
}

.research-news-page .rn-news-card:hover .rn-card-title {
    color: #6f2c91;
}

.research-news-page .rn-news-card:hover .rn-card-arrow {
    transform: translateX(5px);
}

/* --- 响应式设计 --- */

/* 平板 (小于 1100px) */
@media (max-width: 1100px) {
    .research-news-page .rn-container {
        padding: 0 30px;
        column-gap: 40px;
    }
    .research-news-page .rn-news-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 35px 20px;
    }
}

/* 手机 (小于 768px) */
@media (max-width: 768px) {
    .research-news-page {
        padding: 30px 0;
    }
    .research-news-page .rn-container {
        display: block;
        padding: 0 20px;
    }
    
    .research-news-page .rn-page-title {
        font-size: 28px;
        margin-bottom: 20px;
        padding-bottom: 15px;
    }
    
    .research-news-page .rn-page-title::before {
        height: 32px;
    }

    .research-news-page .rn-cat-title {
        display: none; /* 手机端隐藏分类标题，更加简洁 */
    }

    .research-news-page .rn-cat-list {
        flex-direction: row;
        gap: 24px;
        border-bottom: 1px solid #eeeeee;
        padding-bottom: 15px;
        margin-bottom: 30px;
    }

    .research-news-page .rn-cat-item {
        padding-left: 0;
        padding-bottom: 8px;
    }

    .research-news-page .rn-cat-item.active::before {
        display: none;
    }

    /* 手机端选中状态使用紫色下划线 */
    .research-news-page .rn-cat-item.active {
        border-bottom: 2px solid #6f2c91;
    }

    .research-news-page .rn-news-grid {
        grid-template-columns: 1fr;
        gap: 25px;
    }

    /* 手机端图片比例为 16/10 */
    .research-news-page .rn-card-image {
        aspect-ratio: 16 / 10;
    }
}