Guideline: User override of styles.
Allow user specified guidelines (i.e. "important!" style)
to override any author-generated style sheets. This is important
for overriding small font sizes as well as undesired color
Guideline: Units of measure.
Use relative rather than absolute units of measurement (em
Guideline: Generated content.
Ensure that important content appears in the document object.
Text generated by style sheets is not part of the document
source and will not be available to assistive technologies
that access content through the Document Object Model Level
Instead of using deprecated presentation elements and attributes,
use the many CSS properties to control font characteristics:
‘font-family’, ‘font-size’, ‘font-size-adjust’, ‘font-stretch’,
‘font-style’, ‘font-variant’, and ‘font-weight’.
If you must use HTML elements to control font information,
use BIG and SMALL, which are not deprecated.
Guideline: Text style effects.
Avoid causing text to blink until such time that this can be
overridden by the user.
Guideline: Text instead of images.
Use text instead of images containing text wherever possible.
If it is necessary to render text via an image, an alternate
text tag must be provided.
Guideline: Text formatting and position.
Use style sheets to control layout and presentation.
Ensure background and foreground colors provide appropriate
contrast. Ensure information is not in color alone.
Guideline: Providing contextual clues in HTML
Markup lists and list items appropriately.
Guideline: Layout, positioning, layering,
Use style sheets to control layout and presentation. Do not
use tables for layout unless table data makes sense when linearized.
Guideline: Rules and borders.
Organize documents so they may be read without style sheets.
Guideline: Using style sheet positioning and
markup to transform gracefully.
Removal of associated style sheets should still allow tabular
data to be read in a way which makes logical sense.
Guideline: Creating movement with style sheets
Until it is possible for users to freeze moving content, avoid
using movement in pages.