css text effect, text color has light and shadow flow

.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;

}