#ajax_spinner {
    --hue: 223;
    --bg: hsl(var(--hue),90%,95%);
    --fg: hsl(var(--hue),90%,5%);
    --trans-dur: 0.3s;
    font-size: 5px;
    /*font-size: calc(16px + (24 - 16) * (100vw - 320px) / (1280 - 320));*/
    position: fixed;
    width: 100%;
    height: 100%;
    z-index: 999999999;
    background: rgba(0, 0, 0, 0.5);
}
#ajax_spinner main {
    margin-right: auto;
    margin-left: auto;
    width: 80px;
    margin-top: calc(25% - 20px);
    position: relative;
}
.ip {
    width: 16em;
    height: 8em;
}
.ip__track {
    stroke: hsl(var(--hue),90%,90%);
    transition: stroke var(--trans-dur);
}
.ip__worm1,
.ip__worm2 {
    animation: worm1 2s linear infinite;
}
.ip__worm2 {
    animation-name: worm2;
}

/* Dark theme */
@media (prefers-color-scheme: dark) {
    :root {
        --bg: hsl(var(--hue),90%,5%);
        --fg: hsl(var(--hue),90%,95%);
    }
    .ip__track {
        stroke: hsl(var(--hue),90%,15%);
    }
}

/* Animation */
@keyframes worm1 {
    from {
        stroke-dashoffset: 0;
    }
    50% {
        animation-timing-function: steps(1);
        stroke-dashoffset: -358;
    }
    50.01% {
        animation-timing-function: linear;
        stroke-dashoffset: 358;
    }
    to {
        stroke-dashoffset: 0;
    }
}
@keyframes worm2 {
    from {
        stroke-dashoffset: 358;
    }
    50% {
        stroke-dashoffset: 0;
    }
    to {
        stroke-dashoffset: -358;
    }
}