CSS: Attribute Substring Selectors
a[href$='.pdf'], a[href$='.PDF'] {
padding-left:20px;
background:transparent url(../img/pdf_icon.png) center left no-repeat;
}
a[href$='.doc'], a[href$='.rtf'], a[href$='.txt'], a[href$='.wps'] {
padding-left: 20px;
background: transparent url(../img/doc_icon.png) center left no-repeat;
}