.loader {
    width: 60px;
    aspect-ratio: 2;
    --_g: no-repeat radial-gradient(circle closest-side, #000 90%, #0000);
    background: var(--_g) 0% 50%, var(--_g) 50% 50%, var(--_g) 100% 50%;
    background-size: calc(100% / 3) 50%;
    animation: l3 1s infinite linear;
}

@keyframes l3 {
    20% {
        background-position: 0% 0%, 50% 50%, 100% 50%;
    }

    40% {
        background-position: 0% 100%, 50% 0%, 100% 50%;
    }

    60% {
        background-position: 0% 50%, 50% 100%, 100% 0%;
    }

    80% {
        background-position: 0% 50%, 50% 50%, 100% 100%;
    }
}

/* Loader styling */
#loader {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    z-index: 9999;
    display: none;
    /* Initially hidden */
}

/* Background overlay styling */
#overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    /* Semi-transparent background */
    z-index: 9998;
    display: none;
    /* Initially hidden */
}