Use relative units for responsive layouts
SkillDev toolsresponsive-units is a skill for AI agents that reviews CSS for proper use of relative units for responsive layouts. It examines stylesheets, component styles, and responsive behavior, and checks the rendered layout across breakpoints and interaction states before proposing a fix.
Available today. Use it from your connected AI after setup.
No other account needed.
Have an AI agent that supports loading skills.
Then ask your AI: use the Use relative units for responsive layouts skill
What your AI can do with it
- Review stylesheets for proper use of relative units
- Review component styles for responsive behavior
- Check the rendered layout across breakpoints
- Check layouts across interaction states before proposing a fix
Getting started
- Have an AI agent that supports loading skills.
- Add the responsive-units skill to the agent's available skills.
- Ask the agent to review a stylesheet or component styles for relative unit usage and responsive behavior.
- Have the agent check the rendered layout across breakpoints and interaction states before accepting any proposed fix.
What this skill tells your AI
The instructions your AI receives, as published by thedaviddias/front-end-checklist in skills/responsive-units/SKILL.md and read by ahel’s review.
Fixed pixel values override user browser preferences, making your site inaccessible to users who increase their default font size (a common accommodation for low vision). Relative units also reduce the number of breakpoints needed — elements naturally adapt to available space rather than requiring explicit overrides at every viewport width.
Quick Reference
- Use rem for font sizes — it respects user browser font size preferences
- Use % or flex/grid for widths — they adapt to the parent container
- Use em for component-relative spacing (padding, border-radius)
- Use clamp() for fluid typography that scales smoothly between breakpoints
Check
Find all px-based font-size, width, and padding values in this CSS file that should use relative units instead.
Fix
Convert fixed px font sizes to rem equivalents and replace fixed widths with percentage or relative alternatives.
Explain
Explain the difference between rem, em, %, vw, and vh, and when to use each one.
Code Review
Review stylesheets, component styles, and responsive states related to Use relative units for responsive layouts. Flag exact selectors, declarations, or breakpoints that violate the rule in the rendered UI.
For full implementation details, code examples, and framework-specific guidance,
see references/rule.md.
Rule page: https://frontendchecklist.io/en/rules/css/responsive-units
Signals
- GitHub stars
- 74k
- Forks
- 7k
- Last commit
- Aug 2026
Questions
- When should the agent use this skill?
- When reviewing stylesheets, component styles, and responsive behavior related to using relative units for responsive layouts.
- What does the agent check before proposing a fix?
- It checks the rendered layout across breakpoints and interaction states before proposing a fix.
- What kinds of files does it review?
- Stylesheets and component styles, with a focus on responsive behavior.
Advanced
- Item type
- skill
- Key
responsive-units- Source
- github.com/thedaviddias/front-end-checklist