%placeholder { $width: 800px; $bg-color: $white; &::after { @include fit-positions; content: ""; animation-duration: 1.25s; animation-fill-mode: forwards; animation-iteration-count: infinite; animation-name: __placeholder; animation-timing-function: linear; background: linear-gradient( to right, transparent 10%, mix-alpha($bg-color, 60%) 18%, transparent 33% ); background-size: $width 100%; position: absolute; } @keyframes __placeholder { from { background-position: #{ - $width / 2 } 0; } to { background-position: #{ $width / 2 } 0; } } }