.video {
    position: relative;
    display: block;
    --w: 1;
    --h: 1;
    padding-bottom: calc(100% / var(--w) * var(--h));
    background: var(--color-black);
}
.video iframe,
.video video
{
    position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    border: 0;
}
.video .k-aspect-ratio > * {
    object-fit: cover;
}