.button{overflow:hidden;position:relative}.button span{pointer-events:none;position:relative}.button:before{--size:0;background:radial-gradient(circle closest-side,#fbcd01,#fdd000);content:"";height:0;height:var(--size);left:0;position:absolute;top:0;transform:translate(-10%,-10%);transition:width .2s ease,height .2s ease;width:0;width:var(--size)}.button:hover:before{--size:400px}