css文字效果，文字颜色有光影流动

.sq_start {
 position: absolute;
 bottom: 10%;
 left: 50%;
 z-index: 3;
 margin-left: -50px;
 width: 100px;
 height: 20px;
 font-size: 18px;
 background: -webkit-gradient(linear,left top,right top,color-stop(0, #549A66),color-stop(0.3, #3CAF5A),color-stop(0.5, white),color-stop(0.7, #3CAF5A),color-stop(1, #3CAF5A));
 background-clip: text;
 -webkit-background-clip: text;
 -webkit-text-fill-color: transparent;
 text-fill-color: transparent;
 -webkit-animation: slidetounlock 4s 

linearinfinite;

 animation: slidetounlock 4s 

linear infinite;

}