You are encouraged to use style sheets instead. Don't use color combinations that cause problems for people with color blindness in its various forms. If you use a background image or set the background color, then be sure to set the various text colors as well. When practical, adopt common conventions to minimize user confusion. When allotting space among elements competing for that space, user agents allot pixel and percentage lengths first, then divide up remaining available space among relative lengths.
Length values are case-neutral.
For information on specifying language codes in HTML, please consult the section on language codes . Whitespace is not allowed within the language-code. Language codes are case-insensitive. Names of character encodings are case-insensitive. User agents must follow the steps set out in the section on specifying character encodings in order to determine the character encoding of an external resource.