Accessibility

CSS

CSS is a simple tool which allows web developers to create a site that benefit accessibility . CSS allows users to override author styles. This is very important to users who cannot perceive a page with the author's chosen fonts and color. CSS also allows users to view documents with their own preferred fonts, colors, etc. by specifying them in a user style sheet.

Allowing CSS to seperate the structure and layout of the site greatly improves how accessible the site is. If HTML elements are used for their correct purposes, then this improves the structural coding of the site, and in turn the code is cleaner and esaier to maintain.
Text-only browsers and screen readers benefit as they can take advantage from this enhanced structural information to improving within-page browsing. For example, a screen reader can allow direct navigation between page headings, but only if HTML heading elements (e.g. h1) are used. If text is marked up to resemble headings, this potential benefit is lost. The same goes for table headings, the absence of which can mean a data table becomes almost incomprehensible when heard using a screen reader.