// @include aspect($w: 16, $h: 9); @mixin aspect($w: 16, $h: 9) { aspect-ratio: #{$w} / #{$h}; @supports not (aspect-ratio: #{$w} / #{$h}) { &::before { content: ''; float: left; padding-top: calc((#{$h} / #{$w}) * 100%); } &::after { content: ''; display: block; clear: both; } } }