CSS Specificity Debugging: A Practical Guide

Overriding styles with !important leads to chaos. Debug specificity properly.

1. Inspect the Element

Open DevTools, select element, view Computed panel:

• Which property value wins?
• Which selector applied it?

2. Calculate Specificity

Recall:

• Inline: 1000
• ID: 100
• Class/attr/pseudo-class: 10
• Element/pseudo-element: 1

3. Identify Unintended Overrides

Look for long nested selectors from utility frameworks or component libs.

4. Simplify the Source

Refactor heavy selectors to BEM-like small class tokens.

5. Introduce Utilities / Tokens

Favor Tailwind or utility classes over deep cascades.

6. Use Layering (if available)

With modern CSS @layer, structure base, components, utilities.

7. Avoid Escalation

Do not increase specificity unless necessary. Resist adding IDs.

8. Add Regression Test (Visual)

Use Storybook snapshots or Percy to detect future clashes.

9. Remove Dead CSS

Run npx lightningcss --analyze or PurgeCSS to spot unused selectors.

10. Style Hygiene Checklist

Selector causing issue:
Expected vs actual:
Root cause:
Refactor applied:
Follow-up cleanup:
Copy code

Predictable styles scale teams.