ガイド
アクセシビリティのために文字コントラストを確認する方法
WCAGを基準に、文字コントラストを実務で反復チェックする方法を解説します。
文字コントラストの確認は、UI品質をすぐ改善できる施策です。短い手順を繰り返すだけで多くの問題を早期に防げます。
Identify text types first
List body text, helper text, button labels, and links.
Smaller text needs stronger contrast than large headings.
Test each pair with a checker
Enter foreground and background colors and read both ratio and WCAG results.
Document combinations that fail so fixes stay organized.
Fix by changing lightness first
Try lightness adjustments before replacing the full hue.
This usually preserves your visual identity while improving readability.
Retest interactive states
Validate default, hover, focus, active, and disabled states.
Accessibility failures often hide in non-default states.
Where to apply this
- Landing page updates.
- Product UI reviews.
- Design handoff QA.
Make contrast part of QA
Treat contrast checks as a standard release step, just like spelling or layout checks.