Make sure that information about the meaning and structure of your content are conveyed by more than the visual presentation of your content.
Official Requirements:
1.3.1 Info and Relationships: Information, structure, and relationships conveyed through presentation can be programmatically determined or are available in text.
How to fix:
- Use HTML's semantic elements to convey meaning, rather than visual presentation. For example, use an H3 element, rather than bolded and colored text set off by a line break. Use real list markup rather than a table of text and bullet images. Use paragraphs rather than a couple of line breaks. HTML 5 contains many new useful semantic elements.
- Use label elements to associate form labels with their elements.
- Use color and text to indicate required fields.
- Use the TH element, with the scope attribute, to indicate table structure.