In (X)HTML there are 6 levels of headings, h1 through to h6. To maintain the logical structure of your documents, headings should follow a logical progression. Headings of level 3 shouldn't follow directly from headings of level 1, only from headings of level 2. You should always try to maintain a distinction between appearance and logic. Simply because an element is a heading of level 2 does not mean that it will be rendered larger and bolder than regular text in the document. Style sheets allow a web designer to very easily apply any styling to a heading. Keep in mind too, that there are browsers which don't display information in a visual way, relying on text to speech conversion, or braille conversion. For maximum accessibility, structural elements such as headings should be used correctly, and appropriately. Also see structure.