A WCAG conformance level grades how strongly a website meets applicable accessibility success criteria. WCAG 2.1 defines three levels: A, AA, and AAA. section 4.4.2
Interpret the levels as progressively stronger targets:
- Level A sets the bare minimum needed for most people to see, operate, and understand a website. section 4.4.2
- Level AA raises the target so more people can perceive, use, and understand the website; it is commonly the practical middle ground. section 4.4.2
- Level AAA is very strict and is not recommended as a general requirement for entire sites because some criteria cannot be satisfied for every kind of content. section 4.4.2
A contrast-friendly fallback
A blue chart bar against light gray may achieve only 1.93:1 contrast, below the AA target of 3:1. Adding a dark-gray border raises the measured contrast to 8.7:1. When a preferred palette cannot meet a guideline, an accessible alternative, such as a palette toggle, can provide another compliant path. section 4.4.2
