body {
}
#myVideo {
    position: fixed;
    right: 0;
    bottom: 0;
    min-width: 100%;
    min-height: 100%;
}

.content {
    position: fixed;
    bottom: 0;
   
    color: #3d3c3c;
    width: 100%;
    padding: 20px;
    height: 100vh;
}

#myBtn {
    width: 200px;
    font-size: 18px;
    padding: 10px;
    border: none;
    background: #000;
    color: #fff;
    cursor: pointer;
}

    #myBtn:hover {
        background: #ddd;
        color: black;
    }