soapbox/app/styles/components/media-gallery.scss

.media-gallery {
  box-sizing: border-box;
  margin-top: 8px;
  overflow: hidden;
  border-radius: 4px;
  position: relative;
  width: 100%;
  height: auto;
  background-color: var(--brand-color--faint);
}

.media-gallery__item {
  border: 0;
  box-sizing: border-box;
  display: block;
  float: left;
  position: relative;
  border-radius: 4px;
  overflow: hidden;

  &__icons {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 100px;
  }
}

.media-gallery__item-thumbnail {
  cursor: zoom-in;
  display: block;
  text-decoration: none;
  color: var(--primary-text-color--faint);
  line-height: 0;
  position: relative;
  z-index: 1;

  &,
  .still-image {
    height: 100%;
    width: 100%;

    img {
      object-fit: cover;
    }
  }

  .still-image--play-on-hover::before {
    content: 'GIF';
    position: absolute;
    color: var(--primary-text-color);
    background: var(--foreground-color);
    bottom: 6px;
    left: 6px;
    padding: 2px 6px;
    border-radius: 2px;
    font-size: 11px;
    font-weight: 600;
    pointer-events: none;
    opacity: 0.9;
    transition: opacity 0.1s ease;
    line-height: 18px;
  }
}

.status__wrapper, .detailed-status__wrapper {
  .media-gallery__item-thumbnail {
    &,
    .still-image {

      img {
        object-fit: contain;
      }
    }
  }
}

.media-gallery__preview {
  width: 100%;
  height: 100%;
  object-fit: cover;
  position: absolute;
  top: 0;
  left: 0;
  z-index: 0;
  background: var(--background-color);

  .still-image--play-on-hover::before {
    content: 'GIF';
    position: absolute;
    color: var(--primary-text-color);
    background: var(--foreground-color);
    bottom: 6px;
    left: 6px;
    padding: 2px 6px;
    border-radius: 2px;
    font-size: 11px;
    font-weight: 600;
    pointer-events: none;
    opacity: 0.9;
    transition: opacity 0.1s ease;
    line-height: 18px;
  }

  &--hidden {
    display: none;
  }
}

.media-gallery__gifv {
  height: 100%;
  overflow: hidden;
  position: relative;
  width: 100%;
}

.media-gallery__item-gifv-thumbnail {
  cursor: zoom-in;
  height: 100%;
  object-fit: cover;
  position: relative;
  width: 100%;
  z-index: 1;
  transform: none;
  top: 0;
}

.media-gallery__item-thumbnail-label {
  clip: rect(1px 1px 1px 1px); /* IE6, IE7 */
  clip: rect(1px, 1px, 1px, 1px);
  overflow: hidden;
  position: absolute;
}

.media-gallery__gifv__label,
.media-gallery__filename__label,
.media-gallery__file-extension__label {
  display: block;
  position: absolute;
  color: var(--primary-text-color);
  background: rgba($base-overlay-background, 0.5);
  bottom: 6px;
  left: 6px;
  padding: 2px 6px;
  border-radius: 2px;
  font-size: 11px;
  font-weight: 600;
  z-index: 1;
  pointer-events: none;
  opacity: 0.9;
  transition: opacity 0.1s ease;
  line-height: 18px;
}

.media-gallery__gifv {
  &.autoplay {
    .media-gallery__gifv__label {
      display: none;
    }
  }

  &:hover {
    .media-gallery__gifv__label {
      opacity: 1;
    }
  }
}