transform实现按钮边框旋转效果

color:#0ebeff;
font-size:24px;
background:#000;
border:none;
outline:none;
z-index:1;
border-radius:10px;
overflow:hidden;

position:relative;

button::before {
    content:'';
    position:absolute;
    background:#f40;
    width:200%;
    height:200%;
    z-index:-2;
    left:50%;
    top:50%;
    transform-origin: 0 0;
    animation:rotate 3s infinite linear;
}

#keyframes rotate {
    to {
        transform:rotate(1turn)
    }
}

button ::after{
    content:'';
    position:absolute;
    background:#000;
    width:calc(100% - 4px);
    height:calc(100% - 4px);
    left:2px;
    top:2px;
    border-radius:10px;
    z-index:-1
}