.clearfix:after {
   content: " "; /* Older browser do not support empty content */
   visibility: hidden;
   display: block;
   height: 0;
   clear: both;
}
.grow {
    width: 800px;
    
    height:40px;
    -webkit-animation-name: example; /* Chrome, Safari, Opera */
    -webkit-animation-duration: 1s; /* Chrome, Safari, Opera */
    animation-name: normalanim;
    animation-duration: 1s;
}

/* Chrome, Safari, Opera */
@-webkit-keyframes normalanim {
        from {width:0px;}
		to {width:800px;}
}

/* Standard syntax */
@keyframes normalanim {
    from {width:0px;}
    to {width:800px;}
}