Vertical spacing in text-decoration: underline using CSS

text-decoration_underline.css

/*
Adjust vertical space by adjusting 71%
Adjust line thickness by adjusting 71% and 72%
*/
a:hover {
    background: -moz-linear-gradient(top,  rgba(0,0,0,0) 0%, rgba(0,0,0,0) 71%, #FFFFFF 71.1%, #FFFFFF 72%, rgba(0,0,0,0) 72.1%, rgba(0,0,0,0) 100%); /* FF3.6+ */
    background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,rgba(0,0,0,0)), color-stop(71%,rgba(0,0,0,0)), color-stop(71.1%,#FFFFFF), color-stop(72%,#FFFFFF), color-stop(72.1%,rgba(0,0,0,0)), color-stop(100%,rgba(0,0,0,0))); /* Chrome,Safari4+ */
    background: -webkit-linear-gradient(top,  rgba(0,0,0,0) 0%,rgba(0,0,0,0) 71%,#FFFFFF 71.1%,#FFFFFF 72%,rgba(0,0,0,0) 72.1%,rgba(0,0,0,0) 100%); /* Chrome10+,Safari5.1+ */
    background: -o-linear-gradient(top,  rgba(0,0,0,0) 0%,rgba(0,0,0,0) 71%,#FFFFFF 71.1%,#FFFFFF 72%,rgba(0,0,0,0) 72.1%,rgba(0,0,0,0) 100%); /* Opera 11.10+ */
    background: -ms-linear-gradient(top,  rgba(0,0,0,0) 0%,rgba(0,0,0,0) 71%,#FFFFFF 71.1%,#FFFFFF 72%,rgba(0,0,0,0) 72.1%,rgba(0,0,0,0) 100%); /* IE10+ */
    background: linear-gradient(to bottom,  rgba(0,0,0,0) 0%,rgba(0,0,0,0) 71%,#FFFFFF 71.1%,#FFFFFF 72%,rgba(0,0,0,0) 72.1%,rgba(0,0,0,0) 100%); /* W3C */
    
    text-decoration: none;
}