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

.login-box, .register-box {
    width: 100%;
    margin: auto;
    position: absolute;
    left: 0;
    right: 0;
    background: rgba(33, 33, 33, 0.51);
    top: 0;
    bottom: 0;
    overflow: hidden;
    padding: 100px 40px;
}
body{
    background: #000;
}