#youtube:hover {
    filter: drop-shadow(0 0 30px white);
}

#youtube {
    filter: drop-shadow(0 0 30px black);
    transition: all 300ms 0s ease;
    opacity: 1;
    animation: youtube-animation 1s ease 0s 1 alternate none running;
    margin-bottom:40px;
}

#youtube iframe {
    width: 56vmax;
    height: 31.5vmax; 
}

@keyframes youtube-animation {
    0% {
        opacity: 0;
    }

    100% {
        opacity: 1;
    }
}