Firefox – Black Background on New (blank) Tab Page

Opening a new tab in Firefox in a dark room can be a blinding experience.  Luckily, there’s an easy way to make the ‘New Tab’ page background black (or any color you want, really).

To start, click on the Firefox menu button, go to ‘Help’, and then click on ‘Troubleshooting Information’.  You should get a page that looks like this:






Click on the ‘Show Folder’ button to open your current profile folder on your PC.  Inside this folder that opened you should see a ‘chrome’ folder (this is unrelated to Google’s Chrome browser).  Open this folder and you’ll find a file called UserContent.css.  If it’s not there, you can create it by starting a new notepad document, just be sure to save it as UserContent.css and not userContent.css.txt.  Open this file with notepad, and at the bottom, paste this CSS code:

#newtab-window {
 background-color: #000000 !important;

Save the file, restart Firefox, and you should be all set.  If you want to change the color from black to something of your own liking, you can reference this page for a list of hexadecimal color codes.

9 thoughts on “Firefox – Black Background on New (blank) Tab Page”

  1. The chrome folder was missing for me as well, but creating it, and then creating the UserContent.css file inside it worked just fine. Thanks!

  2. I made the chrome folder and the css file. I made the css file with notepad plus. It works, when I hit new tab. The first page that opens FF is still the bright white. My FF opens to a blank page. I probably have to change something for about:blank to change that.

  3. Firefox 52.2.0 on Debian GNU/Linux: folder and file name is correct, content is exactly as shown above but still: new tab has a very bright background. Even when I disable “show your top sites”.
    Has the directory or the file name changed?


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