The structure of Web Content Accessibility Guidelines (WCAG) 2.1

Guideline 1.1 – Text Alternatives

• Success Criteria 1.1.1 Non-text Content (Level A)

Guideline 1.2 – Time-Based Media

• Success Criteria 1.2.1 audio-only and video-only (prerecorded) (Level A)
• Success Criteria 1.2.2 captions (prerecorded) (Level A)
• Success Criteria 1.2.3 audio description or media alternative (prerecorded) (Level A)
• Success Criteria 1.2.4 captions (live) (Level AA)
• Success Criteria 1.2.5 audio description (prerecorded) (Level AA)

Guideline 1.3 – Adaptable

• Success Criteria 1.3.1 info and relationships (Level A)
• Success Criteria 1.3.2 meaningful sequence (Level A)
• Success Criteria 1.3.3 sensory characteristics (Level A)
• Success Criteria 1.3.4 orientation (Level AA)
• Success Criteria 1.3.5 identify input purpose (Level AA)

Guideline 1.4 – Distinguishable

• Success Criteria 1.4.1 use of color (Level A)
• Success Criteria 1.4.2 audio control (Level A)
• Success Criteria 1.4.3 contrast (minimum) (Level AA)
• Success Criteria 1.4.4 resize text (Level AA)
• Success Criteria 1.4.5 images of text (Level AA)
• Success Criteria 1.4.10 reflow (Level AA)
• Success Criteria 1.4.11 non-text contrast (Level AA)
• Success Criteria 1.4.12 text spacing (Level AA)
• Success Criteria 1.4.13 content on hover or focus (Level AA)

Guideline 2.1 – Keyboard Accessible

• Success Criteria 2.1.1 keyboard (Level A)
• Success Criteria 2.1.2 no keyboard trap (Level A)
• Success Criteria 2.1.4 character key shortcuts (Level A)

Guideline 2.2 – Enough Time

• Success Criteria 2.2.1 timing adjustable (Level A)
• Success Criteria 2.2.2 pause, stop, hide (Level A)

Guideline 2.3 – Seizures

• Success Criteria 2.3.1 three flashes or below threshold (Level A)

Guideline 2.4 – Navigable

• Success Criteria 2.4.1 bypass blocks (Level A)
• Success Criteria 2.4.2 page titled (Level A)
• Success Criteria 2.4.3 focus order  (Level A)
• Success Criteria 2.4.4 link Purpose (in context) (Level A)
• Success Criteria 2.4.5 multiple ways (Level AA)
• Success Criteria 2.4.6 headings and labels (Level AA)
• Success Criteria 2.4.7 focus visible (Level AA)

Guideline 2.5 – Input Modalities

• Success Criteria 2.5.1 pointer gestures (Level A)
• Success Criteria 2.5.2 pointer cancellation (Level A)
• Success Criteria 2.5.3 label in name (Level A)
• Success Criteria 2.5.4 motion actuation (Level A)

Guideline 3.1 – Readable

• Success Criteria 3.1.1 language of page (Level A)
• Success Criteria 3.1.2 language of parts (Level AA)
  

Guideline 3.2 – Predictable

• Success Criteria 3.2.1 on focus (Level A)
• Success Criteria 3.2.2 on input (Level A)
• Success Criteria 3.2.3 consistent navigation (Level AA)
• Success Criteria 3.2.4 consistent identification (Level AA)

Guideline 3.3 – Input Assistance

• Success Criteria 3.3.1 error identification (Level A)
• Success Criteria 3.3.2 labels or instructions (Level A)
• Success Criteria 3.3.3 error suggestion (Level AA)
• Success Criteria 3.3.4 error prevention (legal, financial, data) (Level AA)

Guideline 4.1 – Compatible

• Success Criteria 4.1.1 parsing (Level A)
• Success Criteria 4.1.2 Name, Role, Value (Level A)
• Success Criteria 4.1.3 status messages (Level AA)