Accessibility: Visual guidelines - Colour, text and layout
Layout and design
Graphic designers and artists should work from the principle of relative, rather than absolute, positioning. Do not assume that an element on a web page will end up appearing at a precise pixel location. Think more in terms of percentages of screen estate and ordering in terms of before/after, etc.
Do not assume a particular resolution of screen. Is the design fluid enough to fill a large monitor and use the larger screen estate or, for small handheld devices, will the design 'wrap' correctly to the width of the smaller display, avoiding horizontal scrolling?
Do not create HTML tables to hold visual components on web pages. Use CSS stylesheets to control positioning of elements such as page decoration or navigation panels. Be very careful of the default HTML code generated by web design tools, for example Fireworks, as this usually creates tables. Anything to do with positioning an element should be implemented in an external stylesheet not on the web page itself.Allow the user to override colours and fonts
Always respect the system or browser settings; users must be able to override the look and feel with preferred colours and font styles. They should be able to increase/decrease font size defaults on their browser or operating system and text should scale/change appropriately.