.video-background { /* class name used in javascript too */
    width: 100%; /* width needs to be set to 100% */
    height: 100%; /* height needs to be set to 100% */
    position: absolute;
    left: 0;
    top: 0;
    z-index: -1;
}

.demo-one {
    width: 90%;
    height: 30vw;
    overflow: hidden;
    border: 15px solid red;
    margin-bottom: 40px;
    position: relative;
}

.video-div {
    height: 30vw;
    overflow: hidden;
    min-height:200px;
    position: relative;
}

.video-div .content {
    text-align: center;
    color: #FFF;
    text-shadow: 1px 1px 2px black; 
}