hexo-theme-keep/source/css/layout/_partial/image-viewer.styl

.image-viewer-container {
  position fixed
  top 0
  left 0
  z-index $z-index-8
  display flex
  align-items center
  justify-content center
  box-sizing border-box
  width 100%
  height 100%
  padding 6%
  background rgba(0, 0, 0, 0)
  visibility hidden
  transition-t("visibility, background", "0, 0", "0.3, 0.3", "ease, ease")

  &.active {
    background rgba(0, 0, 0, 0.5)
    visibility visible

    img {
      padding 2px
      background var(--background-color)
      transform scale(1)
      cursor zoom-out
    }
  }

  img {
    max-width 100%
    max-height 100%
    transform scale(0)
    transition-t("transform", "0", "0.3", "ease")
  }
}