WCAG 2.0 AA

"Web Content Accessibility Guidelines (WCAG) are part of a series of web accessibility guidelines published by the Web Accessibility Initiative (WAI) of the World Wide Web Consortium (W3C), the main international standards organization for the internet. They consist of a set of guidelines for making content accessible, primarily for people with disabilities, but also for all user agents, including highly limited devices, such as mobile phones..." (source: Wikipedia).