.loader {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);

    height: 15px;
    aspect-ratio: 5;
    display: grid;
    --_g: no-repeat radial-gradient(farthest-side, #29399D 94%, #0000);
}

.loader:before,
.loader:after {
    content: "";
    grid-area: 1/1;
    background:
        var(--_g) left,
        var(--_g) right;
    background-size: 20% 100%;
    animation: l32 1s infinite;
}

.loader:after {
    background:
        var(--_g) calc(1*100%/3),
        var(--_g) calc(2*100%/3);
    background-size: 20% 100%;
    animation-direction: reverse;
}

@keyframes l32 {

    80%,
    100% {
        transform: rotate(.5turn);
    }
}