How to Use Browser Developer Tools to Inspect CSS
A beginner, hands-on guide to use browser developer tools to inspect css with browser inspection, exact code-level changes and verification.
By the end: You will implement and verify use browser developer tools to inspect css on a real local/staging page.
You will implement and verify use browser developer tools to inspect css on a real local/staging page.
Key terms before you start
These definitions make the steps easier to follow and help distinguish controls, files and concepts that can look similar at first.
What you need before starting
- A page you are allowed to edit
- Access to the HTML/CSS/JS or CMS/template that renders it
- A modern browser with Developer Tools
Step-by-step tutorial
Every step is shown below. Work through them in order and use each checkpoint to confirm the result before moving on.
Work on a local or staging copy
Open the project containing the website source. If this is a production site, use a staging copy or backup before structural changes.
A browser page is rendered from source files/CMS output; DevTools edits do not save back to the server.
Move it into the actual source and reload.
Open the page in a modern browser
Load the page, then press F12 or Ctrl+Shift+I (Windows/Linux) to open Developer Tools.
DevTools lets you inspect the DOM, applied CSS, computed sizes, requests and console errors.
Move it into the actual source and reload.
Open DevTools
Right-click the target element → Inspect.
This opens Elements with the relevant node selected.
Move it into the actual source and reload.
Read matched rules
In Styles, find declarations affecting the property you care about.
Crossed-out declarations lost the cascade or are overridden.
Use the Styles/Computed panels to trace the final value instead of adding stronger selectors blindly.
Open Computed
Search for width, color, font-size, display etc.
Computed shows the final resolved value after cascade/inheritance.
Use the Styles/Computed panels to trace the final value instead of adding stronger selectors blindly.
Toggle a declaration
Uncheck a CSS property in Styles.
This temporary experiment shows whether the rule causes the problem.
Use the Styles/Computed panels to trace the final value instead of adding stronger selectors blindly.
Type a test value
Edit the value directly in DevTools.
Temporary edits vanish on reload.
Move it into the actual source and reload.
Inspect box model
Use the Layout/Computed box diagram for margin, border, padding and content size.
This is faster than guessing where spacing comes from.
Use the Styles/Computed panels to trace the final value instead of adding stronger selectors blindly.
Copy the fix to source
Open the actual stylesheet/template and apply the tested change.
DevTools does not save production source.
Move it into the actual source and reload.
Test the public/staging URL logged out
Open the final URL in a private/incognito window.
CMS/admin sessions can hide caching, permission or styling differences.
Check caching, loaded asset URL, theme/template and logged-out view.
Document the changed file/rule
Record the file/template/component and purpose of the change in the project notes or version-control commit.
Future maintainers should not have to reverse-engineer why a rule exists.
Check caching, loaded asset URL, theme/template and logged-out view.
Reload the real page and reproduce the result after all temporary DevTools edits are gone.
Concrete examples
Troubleshooting
Move it into the actual source and reload.
Check caching, loaded asset URL, theme/template and logged-out view.
Use the Styles/Computed panels to trace the final value instead of adding stronger selectors blindly.
The change has a traceable reason/location.
Continue with these tutorials
Documentation and references
Use these primary and supporting sources to verify current controls, browser behavior and product-specific details.