.main-box{width:800px;height:600px;margin:10px auto;border:1px solid #c1c1c1}.teacher{background-color:#f4f5f8;min-height:100vh;height:100vh;display:-webkit-box;display:-ms-flexbox;display:flex;display:-webkit-flex;-webkit-box-align:center;-ms-flex-align:center;align-items:center;-webkit-box-pack:center;-ms-flex-pack:center;justify-content:center}.teacher .max-width{max-width:80%;margin:0 auto}.teacher .teacher-box{width:100%;display:-webkit-box;display:-ms-flexbox;display:flex}.teacher .teacher-box .video-div{position:relative;height:80vh}.teacher .teacher-box .video-div video{height:100%}