Any Firefox user knows that when you visit a https:// secure site in Firefox, the location bar background turns from white to an off-yellow color, assuming you are using the default theme. I was personally getting tired of this background, and I discovered how to change that off-yellow color to whatever color you want.

1. Navigate to C:\Program Files\Mozilla Firefox\chrome (Linux users: /usr/lib/firefox/chrome )
2. Make a backup of the file named classic.jar. This is really important. You don’t want to have to reinstall Firefox because you fucked something up.
3. Open classic.jar in a text editor, such as Notepad++ (my personal favorite). Or inside the jar file, find the file /skin/classic/browser/browser.css.
4. Go to line 13304 in classic.jar (line 1233 in browser.css), where it will say:

#urlbar[level=”high”] > .autocomplete-textbox-container,
#urlbar[level=”low”] > .autocomplete-textbox-container {
background-color: #F7F898; /* #F7F898; */
color: #000000;
}

5. Change

background-color: #F7F898;

to whatever hex code you wish. For example, I changed mine to #83FF6B, and now it looks like:

6. Restart Firefox

7. And another tip: Many of Google’s sites, such as Reader, Gmail, History, Bookmarks, and Calendar, have unannounced https:// mirrors, which you should use especially if you are on a public network. Get the Greasemonkey script here.

Thanks to Evan for the Linux and browser.css edits!

-J