searxng/searx/static/plugins/css/infinite_scroll.css

@keyframes rotate-forever {
    0%   { transform: rotate(0deg) }
    100% { transform: rotate(360deg) }
}
.loading-spinner {
    animation-duration: 0.75s;
    animation-iteration-count: infinite;
    animation-name: rotate-forever;
    animation-timing-function: linear;
    height: 30px;
    width: 30px;
    border: 8px solid #666;
    border-right-color: transparent;
    border-radius: 50% !important;
    margin: 0 auto;
}