Attempt to recreate object-fit: cover with just CSS. Not entirely perfect, some dependency on the media element's aspect ratio

img-cover.scss

// Parent container
.container {
  position: relative;
  width: 100vh;
  height: 100vh;
  overflow: hidden;
}

// Can be an img, video, or picture element
.media {
  z-index: 0;
  position: absolute;
  top: 50%;
  left: 50%;
  max-width: 100vw;
  min-width: 100%;
  min-height: 100%;
  width: auto;
  height: auto;
  transform: translateY(-50%) translateX(-50%);

  // Image must have a square or wide aspect ratio
  @media (orientation: portrait) {
    max-width: none;
    max-height: 100vh;
  }

  // If an image has a tall aspect ratio, detect it programmatically and give it this class
  &--tall {
    max-width: none;
    max-height: 100vh;

    @media (orientation: portrait) {
      max-width: 100vw;
      max-height: none;
    }
  }
}