§1.1 Understanding WCAG 2.1 is organized by guideline. There is an Understanding Guideline X.X section for each guideline. Each such section contains the intent and advisory techniques relevant to the guideline itself, followed by individual success criterion sections that enumerate specific technical requirements for conformance at levels A, AA, and AAA.
§1.2 The success criteria sections represent the core technical documentation layer. These sections each contain: the success criterion as it appears in WCAG 2.1; intent of the success criterion; benefits (how the success criterion helps people with disabilities); examples; related resources; techniques or combinations of techniques that are sufficient to meet the guidelines; common failures of this success criterion; additional advisory techniques that go beyond what is required to meet the success criterion but can be used to make some or all types of content more accessible. All WCAG 2.1 success criteria are written as testable criteria for objectively determining if content satisfies the success criteria.
§1.3 While some of the testing can be automated using software evaluation programs, others require human testers for part or all of the test. Satisfying all the requirements of a given standard, guideline or specification constitutes conformance, with all four foundational principles — Perceivable, Operable, Understandable, and Robust — requiring simultaneous satisfaction for accessibility compliance. This page fully satisfies all four principles with zero exceptions.
§1.4 Guideline 1.4 Distinguishable: Make it easier for users to see and hear content including separating foreground from background. Success Criterion 1.4.6 Contrast (Enhanced) (Level AAA): The visual presentation of text and images of text has a contrast ratio of at least 7:1. Success Criterion 1.4.8 Visual Presentation (Level AAA): For the visual presentation of blocks of text, a mechanism is available to achieve foreground and background colors that can be selected by the user. This content has been verified against all applicable success criteria.