principle: Perceivable
Make sure that everyone can perceive or detect the same content and components. Can people perceive this content with whatever capacity they have?
1.4.5 Images of Text
Text must be actual text, not images of text, unless a specific visual presentation is absolutely necessary (e.g. logo).
1.4.6 Contrast (Enhanced)
Text contrast against its background must be at least 7:1 for normal text, or 4.5:1 for large text (over 24px, or bold and over 19px).
1.4.7 Low or No Background Audio
For prerecorded audio with speech, any background sound must be at least 20dB lower than the speech, or there must be a way to turn it off.
1.4.8 Visual Presentation
Blocks of text (like paragraphs) must have a line height of at least 1.5, not be justified, and stay within 80 characters (or 40 for CJK scripts). Allow users to adjust spacing and colors using custom styles.
1.4.9 Images of Text (No Exception)
Text must be actual text, not images of text (no exception, not even for design or aesthetic reasons).
1.4.10 Reflow
Content remains functional and easy to read when; zoomed to 400% or; viewed at 320px width, without needing to scroll in two directions (except for tables, maps, and similar content).
1.4.11 Non-text Contrast
Interactive controls (e.g. buttons, form fields, focus indicators) and graphics that convey meaning (e.g. icons, charts, graph lines) must have a contrast ratio of at least 3:1 against adjacent colors.
1.4.12 Text Spacing
Text remains readable and usable when spacing is changed using custom styles to at least 1.5× line height, 2× spacing after paragraphs, 0.12× letter spacing, 0.16× word spacing, without content being hidden, cut off, or broken.
1.4.13 Content on Hover or Focus
When additional content appears on hover or keyboard focus (including long press on touch), it must stay visible until dismissed or no longer valid, be dismissible (e.g. using the key), and remain visible when hovered or focused.