body{
    margin: 0;
    padding: 0;
}
iframe{
    width: 900px;
    height: 500px;
    margin: 0;
    padding: 0;
    padding-top: 5px;
}
.biaotou{
    background-color: aqua;
    /* margin-left: 15px; */
    font-family: '微软雅黑';
    font-size: 20px;
    font-weight: bold;
}
.main{
    width: 900px;
}