.media-upload-form .category-tabs, 
.media-upload-form tr.category,
.media-upload-form #category-adder,
.media-upload-form .wp-hidden-children{
    display:none;
}

.media-upload-form .category-filter {
    font-size: 12px;
    font-style: italic;
    font-family: sans-serif;
}