.focus-content{
    margin: 78px auto;
    width: 1440px;
}
.nav{
/*    margin-top: 50px;*/
    padding-top: 72px;
    padding-bottom: 50px;
    /*margin-bottom: 100px;*/
    width: 1360px;
  /*  border-style: solid;*/
    /*border-bottom-color: black;
    border-bottom-width: thick;*/
/*    border-top: rgb(200,0,29) solid 2px;*/

}

.bread-item{
    float: left;
}

.nav a:hover {
    color: rgb(200,0,29);
    /*background-color: #0b5ed7;*/
}
.title1{
    width: 1440px;
    height: 54px;
    line-height: 54px;
    color: black;
    font-family: 微软雅黑;
    font-size: 36px;
    text-align: center;
    margin-bottom: 50px;
}


.video-container {
    width: 700px;
    max-width: 100%;
    margin: 0 auto;
    aspect-ratio: 16 / 9;      /* 直接声明 16:9，高自动 = 700×9/16 ≈ 393.75px */
}
.video-container video {
    width: 100%;
    height: 100%;
    display: block;
/*    object-fit: cover; */         /* 视频不满框时裁切填充，或改成 contain */
    background: #000;
}