@keyframes progress-indeterminate { 0% { right: 100%; left: -35%; } 100%, 60% { right: -90%; left: 100%; } } .progress { position: relative; width: 100%; line-height: $progress-height; appearance: none; &::-webkit-progress-bar { background: $gray-100; } &::-webkit-progress-value { background-color: $primary; } &::-moz-progress-bar { background-color: $primary; } &::-ms-fill { background-color: $primary; border: none; } } .progress-sm { height: .25rem; } .progress-bar-indeterminate { &::after, &::before { position: absolute; top: 0; bottom: 0; left: 0; content: ""; background-color: inherit; will-change: left, right; } &::before { animation: progress-indeterminate 2.1s cubic-bezier(.65, .815, .735, .395) infinite; } }