Adding structure to web content makes it more readable and comprehensible to everyone and especially to people with a visual or cognitive impairment that makes reading on-screen content difficult.
Avoid referring to a button, menu, or other item in the page only by its position on the page; instead, use additional information that describes the content.
Color is a powerful visual means of presenting or distinguishing information, but when you use color to identify or distinguish information, make sure that this information is still available to people who can't perceive color.