Loader Bar

:root {
    --loader-bar-primary-color: var(--color-primary, hotpink);
    --loader-bar-secondary-color: lightgrey;
    --loader-bar-border-radius: 2px;
    --loader-bar-width: 100%;
    --loader-bar-height: 20px;
    --loader-bar-easing: cubic-bezier(0.77, 0, 0.175, 1);
}

.loader-bar {
    display: block;
    background: var(--loader-bar-secondary-color);
    border-radius: var(--loader-bar-border-radius);
}

.loader-bar::before {
    content: '';
    display: block;
    width: var(--loader-bar-width);
    height: var(--loader-bar-height);
    background: var(--loader-bar-primary-color);
    border-radius: var(--loader-bar-border-radius);
    animation-name: loader-bar;
    animation-duration: 1.6s;
    animation-iteration-count: infinite;
    animation-timing-function: linear;
    animation-direction: alternate;
    animation-timing-function: var(--loader-bar-easing);
}

@keyframes loader-bar {
    0% {
        transform-origin: left center;
        transform: scaleX(0);
    }
    49.9% {
        transform-origin: left center;
        transform: scaleX(1);
    }
    50.1% {
        transform-origin: right center;
        transform: scaleX(1);
    }
    100% {
        transform-origin: right center;
        transform: scaleX(0);
    }
}