Hello,

Please see the answers in the support question here:

https://support.mozilla.org/en-US/questions/948373

I hope that helps. Let me know if not.

I placed a folder called chrome in %APPDATA%\Mozilla\Firefox\Profiles, added a text file called userChrome.css, and inserted the following code in that file:

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* only needed once */

#bookmarks-view, #historyTree {
  background-color #CFB53B !important;

}

It didn't work. What else am I missing?

I'm following the information found here:

http://kb.mozillazine.org/UserChrome.css

That page links to this one which gives more information on the Profile Folder:

http://kb.mozillazine.org/Profile_folder_-_Firefox

For Windows 7 the profile folder should be in the following location:

C:\Users\<Windows login/user name>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile folder>

I think you missed out the 'Roaming' folder.

Please let me know if that doesn't work.

You can open the correct folder via Help > Troubleshooting Information -- Profile Folder -->> Show folder .

Once that folder is open, close Firefox, create the \chrome\ folder, and place the userChrome.css file in that folder.

Then you can open Firefox.

Or you can use the ChromEdit Plus extension to automatically create that folder and that file, and allowing you to edit userChrome.css from within Firefox. No need to route thru the bowels of Windows for the proper location, and then manually creating the \chrome\ folder and userChrome.css file.
http://webdesigns.ms11.net/chromeditp.html

After checking Troubleshooting Information, I moved the \chrome\ folder to its new location: C:\Users\<my username>\AppData\Roaming\Mozilla\Firefox\Profiles\v9m6tk59.default\chrome

I was missing the \v9m6tk59.default\ directory in the path before.

I've installed ChromEdit Plus which seems to confirm that I now have it in the right place.

The Bookmarks and History sidebars background remain the same baby blue color as when I started trying to change them. What else are we missing?

Sorry if this is a silly question - have you restarted Firefox?

You're missing a colon after background-color. This works for me, but I think that gold-ish color is burned into my vision now. My tastes aim toward soft colors - I use #DDDDDD for the color background of the Sidebar.

 #bookmarks-view, #historyTree {
  background-color: #CFB53B !important;
} 

@EddyC: Not a silly question at all, but I did restart Firefox each time.

@Edmeister: That got it! I may adjust the color to something else, but I wanted to use a color that I knew was distinctive initially.

Thanks to both of you for your help!

Here's a page that I have used to select colors and see the RGB & Hex codes.

http://www.colorschemer.com/online.html