bootstrap利用Font Awesome给选择添加checkbox图标

a {
.btn;  //给a,应用.btn样式，
.btn-sm;
padding-left: 0;
padding-right: 0;
color: @gray;
&:hover,
&:focus,
&:active,
.active & {
color: @link-color;
}

&:before{  //添加checkbox
.icon-FontAwesome();
text-decoration: inherit;
display: inline-block;
speak: none;
content: @check-empty;
width: 16/14em;
text-align: right;
}
&:hover:before,  //鼠标移入打钩
&:focus:before,
&:active:before,
.active &:before {
content: @check;
}
}