1@property --mask {
2  initial-value: 0deg;
3  syntax: "<angle>";
4  inherits: true;
5}
6
7.gradient::after {
8  mask: linear-gradient(#0000, #0000),
9    linear-gradient(#000, #000),
10    conic-gradient(
11      from var(--mask, 0deg),
12      #0000, #000 25%, #0000 25%
13    );
14  mask-clip: padding-box, border-box, border-box;
15  mask-composite: intersect;
16  animation: mask-rotate 6s infinite linear;
17}
18
19@keyframes mask-rotate {
20  to {
21    --mask: 360deg;
22  }
23}