/* 子页面banner */
.page-banner{
    width: 100%;
    height: 200px;
    background: url('https://picsum.photos/1920/400?random=30') center/cover no-repeat;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
}
.page-banner::before{
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,51,102,0.7);
}
.page-banner h2{
    position: relative;
    color: #fff;
    font-size: 32px;
}

/* 子页面内容区 */
.page-content{
    padding: 50px 0;
    line-height: 1.8;
    font-size: 16px;
}
.page-content p{
    margin-bottom: 20px;
}

/* ========== 新增：二级导航样式 ========== */
.sub-nav{
    background: #f8f9fa;
    border-bottom: 1px solid #eee;
    margin-bottom: 30px;
}
.sub-nav-list{
    display: flex;
    list-style: none;
    width: 1200px;
    margin: 0 auto;
}
.sub-nav-list li{
    margin-right: 2px;
}
.sub-nav-list li a{
    display: block;
    padding: 12px 20px;
    color: #333;
    text-decoration: none;
    font-size: 15px;
    transition: background 0.3s ease;
}
.sub-nav-list li a.active{
    background: #003366;
    color: #fff;
}
.sub-nav-list li a:hover:not(.active){
    background: #eee;
}

/* ========== 专业设计页专属（新增图片样式） ========== */
.major-card-list{
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 30px;
    margin-top: 30px;
}
.major-card{
    background: #f8f9fa;
    padding: 25px;
    border-radius: 8px;
    display: flex;
    gap: 20px;
    align-items: flex-start;
}
.major-card-img{
    width: 180px;
    height: 120px;
    border-radius: 4px;
    overflow: hidden;
    flex-shrink: 0;
}
.major-card-img img{
    width: 100%;
    height: 100%;
    object-fit: cover;
}
.major-card-content{
    flex: 1;
}
.major-card h3{
    color: #003366;
    font-size: 20px;
    margin-bottom: 15px;
    border-bottom: 2px solid #003366;
    padding-bottom: 8px;
}
/* 专业内容模块（默认隐藏） */
.major-content{
    display: none;
}
.major-content.active{
    display: block;
}

/* ========== 视频页专属（新增封面+播放样式） ========== */
.video-list{
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 30px;
    margin-top: 30px;
}
.video-item{
    background: #fff;
    border: 1px solid #eee;
    border-radius: 8px;
    overflow: hidden;
    cursor: pointer;
    transition: box-shadow 0.3s ease;
}
.video-item:hover{
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}
.video-cover{
    width: 100%;
    height: 200px;
    position: relative;
}
.video-cover img{
    width: 100%;
    height: 100%;
    object-fit: cover;
}
/* 播放按钮遮罩 */
.video-play-mask{
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.4);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity 0.3s ease;
}
.video-item:hover .video-play-mask{
    opacity: 1;
}
.video-play-icon{
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background: rgba(0,51,102,0.8);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
}
.video-info{
    padding: 15px;
}
.video-info h3{
    color: #003366;
    font-size: 18px;
    margin-bottom: 10px;
}
/* 视频内容模块（默认隐藏） */
.video-content{
    display: none;
}
.video-content.active{
    display: block;
}
/* 视频播放弹窗 */
.video-modal{
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.8);
    z-index: 99999;
    display: none;
    align-items: center;
    justify-content: center;
    padding: 20px;
}
.video-modal.active{
    display: flex;
}
.video-modal-close{
    position: absolute;
    top: 20px;
    right: 30px;
    color: #fff;
    font-size: 30px;
    cursor: pointer;
}
.video-modal-content{
    width: 80%;
    max-width: 1000px;
    aspect-ratio: 16/9;
    background: #000;
}
.video-modal-content video{
    width: 100%;
    height: 100%;
    object-fit: cover;
}

/* 响应式适配 */
@media(max-width:768px){
    .sub-nav-list{
        width: 95%;
        overflow-x: auto;
        white-space: nowrap;
    }
    .major-card-list,
    .video-list,
    .contact-info{
        grid-template-columns: 1fr;
        flex-direction: column;
        gap: 20px;
    }
    .major-card{
        flex-direction: column;
    }
    .major-card-img{
        width: 100%;
        height: 180px;
    }
    .contact-map{
        height: 250px;
    }
    .video-modal-content{
        width: 95%;
    }
}
@media(max-width:480px){
    .video-cover{
        height: 150px;
    }
}