The document provides styling guidelines for a three-level online store layout: 1) The first level is a product listing with white background, icon tabs, red icons on roll-over, and size options separated by a divider using the FBW font. 2) The second level is a product sheet with a large main image, thumbnail images, description, size/price/cart options, and related products separated by a button. 3) The third level is a cart section to display items added for purchase. Size options change based on the region selected.