<style>
.preview{
background-color: rgba(0, 0, 0, 0);
display: flex;
justify-content: center;
align-items: center;
height: 100vh;
}
.loading {
position: relative;
width: 150px;
height: 150px;
border-radius: 50%;
border: 3px solid transparent;
border-top-color: #faf;
animation: rotate 2s linear infinite;
}

.loading::before {
content: "";
position: absolute;
top: 5px;
right: 5px;
bottom: 5px;
left: 5px;
border-radius: 50%;
/* transparent透明 */
border: 3px solid transparent;
border-top-color: #fcc;
animation: rotate 3s linear infinite;
}

.loading::after {
content: "";
position: absolute;
top: 15px;
right: 15px;
bottom: 15px;
left: 15px;
border-radius: 50%;
/* transparent透明 */
border: 3px solid transparent;
border-top-color: #fcf;
/* linear匀速 infinite持续 */
animation: rotate 1.5s linear infinite;
}

@keyframes rotate {
0% {
transform: rotate(0);
}

100% {
transform: rotate(360deg);
}
}
</style>
<div class="loading">  </div>