Use relative units in CSS |
WAI / WCAG 1.0 Priority 2 checkpoint 3.4
Issue Description The page refers to CSS properties that are specified using absolute units (such as 'in', 'px', 'mm') rather than relative units (such as '%', 'em'). These units are used in STYLE attributes or in external CSS files linked to via the LINK element.
How to fix Use relative rather than absolute units in style sheet property values. Replace all occurrences of units like 'px', 'pt', 'pc', 'cm', 'mm' with percentages or 'em'. Use absolute units only when the type of device that will be used by the website visitor is certain (like a webTV), or in cases where the object to be displayed has a geometry that cannot be changed without becoming distorted (like a gif image).

It is best to avoid using absolute units for font size.

Issue Explanation Whenever possible it is best to use relative units. In this way the visual layout of the page will be "liquid", in the sense that it can adapt to the specific browser being used, the specific screen that supports it, and the font size that a user might want to select as a default.