This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

What is the modern way to style the Dev Tools area through userChrome.css

more options

What is the modern way to style the Dev Tools area through userChrome.css? It appears that whatever techniques were used in 2018, don't apply today because I tried them all.

How should the CSS syntax look for styling the inspector, debugger, etc... (i.e. change the font size and font family types).

I'm on FireFox 97.0

Many thanks!

What is the modern way to style the Dev Tools area through userChrome.css? It appears that whatever techniques were used in 2018, don't apply today because I tried them all. How should the CSS syntax look for styling the inspector, debugger, etc... (i.e. change the font size and font family types). I'm on FireFox 97.0 Many thanks!

Chosen solution

It likely doesn't work because you need to place the code in userContent.css.

What CSS code did you try ?

Read this answer in context 👍 0

All Replies (4)

more options

Seçilmiş Həll

It likely doesn't work because you need to place the code in userContent.css.

What CSS code did you try ?

more options

Before you answered, I originally tried the following...

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* set default namespace to XUL */

@-moz-document url-prefix(chrome: //devtools/content/) {

 .devtools-monospace {
   font-family:arial !important;
   font-size: 20px !important;
   line-height:3;
 }

}

Any recommendations?

Modified by kensley.lewis

more options

This code in userContent.css should work. Do not add the @namespace line.

@-moz-document url-prefix(chrome://devtools/content/) {
 .devtools-monospace {
   font-family:arial !important;
   font-size: 20px !important;
   line-height:3;
 }
}

more options

Absolutely fantastic!

Thanks

Modified by kensley.lewis