.ratio {
    position: relative;
    width: 100%;
    display: block;
}
.ratio > * {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}
.ratio::before {
    content: "";
    display: block;
    padding-top: var(--bs-aspect-ratio);
}
.ratio-16x9 {
    --bs-aspect-ratio: 56.25%;
}