wanghaisheng User Preference Respect
The operating system already knows what the user needs. Your job is to listen and respond. These preferences exist because people set them deliberately — ignoring them overrides the user's own accessibility decision.
The Preferences
prefers-reduced-motion
What it means: user experiences discomfort or harm from motion. What to do:
- Disable all decorative animation
- Replace slide/fade transitions with instant state changes
- Keep essential motion (loading spinners) but simplify
- Disable parallax, scroll-triggered animation, and auto-advance
- Never override this preference
How to detect: @media (prefers-reduced-motion: reduce)
prefers-contrast
What it means: user needs stronger visual distinction. What to do:
- Increase contrast beyond WCAG minimums
- Replace subtle shadows and gradients with solid borders
- Make focus indicators bolder and more visible
- Remove transparency and blur effects
- Increase border widths on interactive elements
How to detect: @media (prefers-contrast: more)
prefers-color-scheme
What it means: user prefers light or dark interface. What to do:
- Provide genuine dark mode (not just inverted colours)
- Ensure all content is legible in both modes
- Test images, charts, icons, and illustrations in both
- Don't use pure black (#000) on dark mode — use dark grey (#1a1a1a) for less eye strain
- Remember: dark mode is not just aesthetic — it reduces eye fatigue and helps some people with light sensitivity
How to detect: @media (prefers-color-scheme: dark)
forced-colors
What it means: user has enabled Windows High Contrast or similar. What to do:
- Don't fight the system colour override
- Ensure borders and outlines define interactive elements (the system will strip your colours)
- Use transparent borders that become visible in forced-colors mode
- Test that all interactive elements remain distinguishable
- Don't rely on background colour alone to indicate state
How to detect: @media (forced-colors: active)
prefers-reduced-transparency
What it means: user finds transparent elements hard to read. What to do:
- Replace semi-transparent backgrounds with solid ones
- Remove frosted glass / backdrop blur effects
- Ensure overlays are fully opaque
How to detect: @media (prefers-reduced-transparency: reduce)
Implementation Principles
Progressive Enhancement
- Build the accessible version first
- Add motion, transparency, and visual flourishes as enhancements
- When a preference is detected, you're removing the enhancement, not degrading the experience
Don't Ask — Detect
- Don't make users configure accessibility settings in your app when the OS already has the setting
- Detect and respond automatically
- If you offer additional settings, they should layer on top of system preferences, not replace them
Test Every Preference
- Test with each preference enabled individually
- Test with combinations (reduced motion + high contrast + dark mode)
- Verify that the interface is complete and usable in every state
- Automated tests can check that media queries exist — manual testing verifies they work
Assessment Checklist
- prefers-reduced-motion is detected and all decorative motion stops
- prefers-contrast is detected and visual contrast increases
- prefers-color-scheme is detected and theme switches
- forced-colors mode doesn't break interactive elements
- Combinations of preferences work together
- No preference is overridden or ignored