.block-withbg {
    position: relative;
    height: 700px;
    background-blend-mode: multiply;
    background-color: rgba(0, 0, 0, 0.342);
    /*进行视频裁剪*/
    overflow: hidden;
    display: block;
    z-index: 1;
    background-image: url("https://itsz1shu.github.io/img/tiangongnorth.png");
    background-size: cover;
    border-top: 2px dotted rgb(108, 108, 108);
}

.title-left{
    font-size: 50px;
    font-family: "Microsoft YaHei";
    letter-spacing: 10px;
    font-weight: bold;
    margin-left: 80px;
    margin-top: 200px;
    color: white;
    z-index: 20;
}

.subtitle-left{
    font-size: 20px;
    font-family: "Microsoft YaHei";
    letter-spacing: 10px;
    font-weight: normal;
    margin-left: 80px;
    margin-top: 10px;
    color: white;
    z-index: 20;
}

.content-left{
    padding-top: 50px;
    margin-left: 80px;
    margin-right: 15%;
    font-size: 20px;
    font-family: "STSong";
    letter-spacing: 10px;
    font-weight: lighter;
    line-height: 24px;
    width: 40%;
    color: white;
    margin-bottom: 20px;

}
.content-left-link{
    font-size: 20px;
    margin-left: 0;
    padding: 0;
    font-family: "STSong";
    letter-spacing: 10px;
    font-weight: lighter;
    line-height: 24px;
    text-decoration: underline;
    color: white;

}

.content-left-link:hover{
    padding-top: 50px;
    font-size: 20px;
    margin-left: 0;
    font-family: "STSong";
    letter-spacing: 10px;
    font-weight: lighter;
    text-decoration: underline;
    color: azure;
}

.left-link-button{
    
    font-size: 15px;
    padding-top: 20px;
    margin-left: 80px;
    padding: 5px;
    font-family: "STSong";
    letter-spacing: 5px;
    font-weight: lighter;
    line-height: 24px;
    border-radius: 5px;
    border: 2px solid white;
    color: white;
    justify-content:center;
}

.left-link-button:hover{
    
    font-size: 15px;
    padding-top: 20px;
    margin-left: 80px;
    padding: 5px;
    font-family: "STSong";
    letter-spacing: 5px;
    font-weight: lighter;
    line-height: 24px;
    border-radius: 5px;
    border: 2px solid rgb(189, 189, 189);
    color: rgb(189, 189, 189);
    justify-content:center;
}