This guideline is a part of the English Wikipedia's Manual of Style. Editors should follow it, except where common sense and the occasional exception will improve an article. Before editing this page, please make sure that your revision reflects consensus.
A pair of screenshots showing the effects of red/green colorblindness on legibility
The following guidance aims to improve accessibility in articles (see Wikipedia:Accessibility) as well as ensure that articles look as good as possible:
Ensure that colour is not the only way used to convey important information. Especially, do not use coloured text unless its status is also indicated using another method such as italic emphasis or footnote labels. Otherwise, blind users or readers accessing Wikipedia through a printout or device without a colour screen will not receive that information.
Many readers of Wikipedia may be partially or fully colour blind. Ensure that the colour combinations used in Wikipedia (infoboxes, navigational boxes, graphs, etc.) have an adequate contrast. Use a colour scheme generator to select the colours, and tools for simulating colour blind vision (colorfilter.wickline.org or vischeck.com) to check the result.
Overriding a link colour, especially to red, is confusing and should be avoided.
Be aware of the contrast of both plain text and the blue link text with the background colour and avoid clashes where possible (such as blue writing on a red background).
Web pages can be checked on-line by the developers with AccessColor, which analyses the HTML source for a web page and the Cascading Style Sheets associated, and then calculates the colour contrast and colour brightness between the text and background colours to check that they conform with WCAG 1.0.
Suitable colour contrast for people with vision impairments, including colour blindness, can be tested with the Colour Contrast Analyser or a specific Firefox extension that use the draft algorithms from the W3C.
Overriding font colour
To make a word have colour, use: <span style="color:hex triplet or colour name">text</span>
Examples:
<span style="color:red">red writing</span> shows as red writing
<span style="color:#0f0">green writing</span> shows as green writing
<span style="color:#0000f1">blue writing</span> shows as blue writing
Wikimedia colour schemes
Wikipedia
Wikipedia uses this colour scheme on its Main Page.
Please note that the colour for the border on the lighter boxes is also the colour of the backgrounds of the darker (title) boxes.