在 :after/ :before 使用 font awesome web Icon

.element {
position: relative;
}

/*replace the content value with the
corresponding value from the list below*/

.element:before {
content: "\f000";
font-family: FontAwesome;
font-style: normal;
font-weight: normal;
text-decoration: inherit;
/*--adjust as necessary--*/
color: #000;
font-size: 18px;
padding-right: 0.5em;
position: absolute;
top: 10px;
left: 0;
}