.doc { background: url(file_icons/icon-doc.png) no-repeat 2px top; }
.docx { background: url(file_icons/icon-doc.png) no-repeat 2px top; }
.ppt { background: url(file_icons/icon-ppt.png) no-repeat 2px top; } 
.pdf { background: url(file_icons/icon-pdf.gif) no-repeat 4px 50%; }
.xls { background: url(file_icons/icon-xls.png) no-repeat 2px top; }
.xlsx { background: url(file_icons/icon-xls.png) no-repeat 2px top; }
.doc, .docx, .ppt, .pdf, .xls, .xlsx {padding-right: 12px;}