file-type-icons.css

/* FILE TYPE ICONS */

[class^="file-type-"] a,
[class*=" file-type-"] a {
    background-image: url('../img/file-type-icons.png');
    background-repeat: no-repeat;
    color: transparent;
    font-size: 0;   /* Needed for IE8 */
    line-height: 0; /* Needed for IE8 */
    float: left;
    position: relative;
    width: 35px;
    height: 40px;
}

/* DOC icon */
.file-type-doc a,
.file-type-docx a,
.file-type-odt a,
.file-type-rtf a,
.file-type-txt a,
.file-type-wpd a { background-position: 0px 0px; }

/* PDF icon */
.file-type-pdf a { background-position: -35px 0px; }

/* PPT icon */
.file-type-ppt a,
.file-type-pptx a,
.file-type-odp a{ background-position: -70px 0px; }

/* XLS icon */
.file-type-xls a,
.file-type-xlsx a,
.file-type-ods a,
.file-type-csv a { background-position: -105px 0px; }

/* ZIP icon */
.file-type-zip a,
.file-type-zipx a,
.file-type-gz a,
.file-type-7z a,
.file-type-rar a,
.file-type-tar a { background-position: -140px 0px; }