@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

#spinner {
    width: 30vw;
    height: 30vw;
    max-width: 30vh;
    max-height: 30vh;
    border: 15px solid transparent;
    border-radius: 100%;
    background: #ffffff;
    --_fade_gradient: conic-gradient(#0000 10%,#000), linear-gradient(#000 0 0) content-box;
    mask: var(--_fade_gradient);
    mask-composite: subtract;
    animation: spin 1.75s linear infinite;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    position: absolute;
    margin: auto;
}