html {
    background-color: black;
    overflow: hidden;
}

.cervena {
    background-color: red;
    position: absolute;
    bottom: 0px;
    top: 50%;
    width: 100%;
    height: 100%;
    left: 0px;
}

.video {
    position: absolute;
    top: 50%;
    left: 50%;
    -ms-transform: translate(-50%, -50%);
    transform: translate(-50%, -50%);
    border: 5px solid white;
    border-radius: 8px;
}

.nadpis {
    color: white;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    font-size: 50px;
    position: absolute;
    left: 50%;
    transform: translate(-50%, -50%);
    top: 10%;
}