* {
    box-sizing: border-box;
    margin: 0px;
    padding: 0px;
}

html, body {
    height: 100%;
    width: 100%;
}

main {
    font-family: Arial, Helvetica, sans-serif;
    height: 100%;
    width: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

main img {
    width: 100%;
    width: 400px;
    height: auto;
    max-width: 60vw;
}

.overlay, #yt_player {
    position: fixed;
    top: 0;
    left: 0;
    min-width: 100%;
    min-height: 100%;
    width: auto;
    height: auto;
}
 
.overlay{
    z-index: -1;
}
 
#yt_player{
    z-index: -2;
}