.video-wrapper {
    aspect-ratio: 16 / 9; /* держит пропорции видео на любой ширине */
    width: 100%;
}
 
.video-wrapper__thumb {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform .5s ease, filter .35s ease;
    display: block;
}
.video-wrapper:hover .video-wrapper__thumb {
    transform: scale(1.05);
    filter: brightness(.55);
}


.video-wrapper iframe {
    width: 100%;
    height: 100%;
    border: none;
}