Firefox's style or appearance can be modified by creating a chrome folder inside your Firefox profile folder and then placing a userChrome.css file inside, that includes a custom style rule. The rules you put in the userChrome.css file will override the default styles in Firefox.

Note: Custom style rules might not work every time because of other factors (such as incompatibility with other custom style rules) beyond the Mozilla community's control. Your custom style rule might also stop working each time a new Firefox release comes out.

Here's how to modify Firefox so that tabs are shown below the address (URL) bar instead of at the top:

If your Firefox profile folder already has a chrome folder containing userChrome.css:
Go to https://www.userchrome.org/what-is-userchrome-css.html and copy the CSS rules under the "Move the Tab Bar Below the Other Toolbars" example here into your userChrome.css file. After saving your changes and closing the file, you should turn on your Firefox title bar or menu bar on Windows. (The CSS rules you copied include other suggestions as comments.)

Otherwise, follow these instructions:
(See this help page and our community member's video starting at 8:45 for more information.)

1. Open your currently active profile folder: Type about:support in the Firefox address bar and, under the "Application Basics" section next to "Profile Folder", click Open Folder (Windows) Open Directory (Linux) or Show in Finder (Mac).
   • On Mac, a folder will open that contains your profile folder. Open the selected profile folder (it will be named something like xxxxxxxx.default for a default profile).
2. Create a new folder named chrome inside the profile folder.
   • Create a desktop shortcut to the chrome folder, if you wish, for easier future access.
3. Download and save this file, then move it into that chrome folder:
   https://www.userchrome.org/samples/userChrome-tabs_on_bottom.css
4. Rename the file from "userChrome-tabs_on_bottom.css" to userChrome.css
   • On Windows: If the file you saved was named "userChrome-tabs_on_bottom" (the .css was missing), rename the file userChrome instead (see the note below).
5. Restart Firefox, which will discover the new userChrome file and apply the rules.

Tip: Turn on your title bar, or the menu bar on Windows, after you've made these changes.

Note for Windows users:
On Windows, file name extensions are hidden by default. If the file you downloaded was saved as "userChrome-tabs_on_bottom" without the .css extension, that means Windows is hiding file name extensions. In that case, you must rename the file userChrome so that you don't end up with a file named "userChrome.css.css" that won't work. To set Windows to show file name extensions, see this Microsoft article for Windows 7. See these fileinfo.com articles for Windows 8 and Windows 10.

lolololololol

all that is greek to me. just complained about this exact thing. COULD YOU COME TO MY HOUSE AND DO ALL THAT FOR ME.

I HOPE MOZILLA/FIREFOX IS SENDING YOU A PAYCHECK TO CLEAN UP THEIR CRAP!

UNBELIEVABLE

HOW ABOUT MOZILLA FIX THEIR S-----

Step by step:

1. Open your currently active profile folder: Type about:support in the Firefox address bar and, under the "Application Basics" section next to "Profile Folder", click Open Folder (Windows) Open Directory (Linux) or Show in Finder (Mac).
   • On Mac, a folder will open that contains your profile folder. Open the selected profile folder (it will be named something like xxxxxxxx.default for a default profile).
2. Create a new folder named chrome inside the profile folder.
   • Create a desktop shortcut to the chrome folder, if you wish, for easier future access.
3. Download and save this file, then move it into that chrome folder:
   https://www.userchrome.org/samples/userChrome-tabs_on_bottom.css
4. Rename the file from "userChrome-tabs_on_bottom.css" to userChrome.css
   • On Windows: If the file you saved was named "userChrome-tabs_on_bottom" (the .css was missing), rename the file userChrome instead (see the note below).
5. Restart Firefox, which will discover the new userChrome file and apply the rules.

Tabs on bottom is not the standard setup for Firefox. You can customize it, but that is up to you to customize Firefox to your liking. This forum is mostly staffed by Volunteers, so I'd appreciate you keeping the abuse off this forum or we will close your account.

I have no clue where "my currently active profile folder" is and that is step 1!!!!

So perhaps you will understand that I am not kidding that I am tech challenged.

I appreciate all ya'alls effort but not helping me.

I am sure many know how to do this reprogramming. Unfortunately I am not one of them.

We can help you with step by step instructions if you would like to follow them, but so far you haven't even made an effort in following the steps given above. Why don't you read them and try following the instructions

Well Tyler, the frustration from you volunteers is unbearable. I keep getting the same answer with programming language after I have asked to not receive that as a solution because I am not able to perform such things. How about respecting my request?

Close the thread!!!! I'll start another one.

And Tyler I believe you are wrong about the tabs being on the bottom. I have used firefox for more years than i care to admit and, tabs were always on the bottom until the recent upgrade. what planet are you from?

I have read the instructions. I cant get past step 1. Where is my profile.

Your profile can be found by typing about:profiles in your URL bar and pressing enter.

You are asking to not receive this solution, however it is the only solution for what you want to do.

@ SinDaRella :

I totally understand your frustration, but Tyler Downer is right when he says that tabs on bottom is not the standard setup for Firefox .

When you say that you've always had the tabs on bottom, couldn't it be that you've had the add-on 'Tabs on Bottom' installed (and maybe forgot you even had it)  ? That add-on stopped working as the developer didn't migrate his add-on to Webextensions.

SinDaRella said

And Tyler I believe you are wrong about the tabs being on the bottom. I have used firefox for more years than i care to admit and, tabs were always on the bottom until the recent upgrade. what planet are you from?

In that case, you must have been using an extension for quite awhile now to get the Tabs "on the bottom" - and that extension is probably no longer compatible with Firefox 57+

Mozilla eliminated Tabs "on the bottom" option with the Firefox 29 version that was released on April 29, 2014 - like 3 1/2 years ago. And that was when the now defunct Classic Theme Restorer came about. So maybe that is what you used in the past?

Finally an answer from Happy112 and the ed-meister. Thank you both.

That's right I did have an extension where the tabs were on the bottom. Nonetheless it doesn't solve the problem without having to do all that programming stuff that I am not even going to try. Last time I attempted to do something like that I had to pay someone $100 to come fix my computer.

So I guess i either put up with it or hope that a new extension for colorful tabs on the bottom is developed. OR change my browser.

The End ~~~~~

Tyler, I'm not asking to not receive the solution. I don't know how many times i have to say this. I don't know how to do what the solution is. Perhaps I can find a friend that is computer literate and give them the information so it can be done. Highly doubtful though.

@ SinDaRella :

I now see you mention 'Colorful Tabs', which led me to this extension (which is only half of what you want, but I thought I'd mention it anyway) :

https://addons.mozilla.org/en-US/firefox/addon/colorfultabs/

The reviews aren't all that good, though ......

This whole 'userChrome.css' phenomenon looks pretty daunting, I must admit - but who knows : maybe one day, when you're a bit bored, you'd like to sink your teeth in it and find that it's a actually a piece of cake .....

Would be great though if some developer would create a 'Tabs on Bottom' Webextension ....... (fingers crossed)

Thank you Happy 112. Ill check out the link. I did find a colorful tab extension a few days ago; however the tabs were still on top and it didn't allow for a theme so i disabled it.

Thanks again

SinDaRella said

Thank you Happy 112. Ill check out the link. I did find a colorful tab extension a few days ago; however the tabs were still on top and it didn't allow for a theme so i disabled it.

Yes, in 'Colorful Tabs' the tabs are not on bottom, hence I said that it's only 'half of what you want' ........ bummer, eh  ?

As for the 'userChrome.css' - truth be told : when I first looked at it, to me it was like Chinese with a Russian accent. So, I totally understand your reaction  !

I don't mind having the tabs where they are and always have been - I'm used to them being there. Maybe you'll get used to it too ....... (Or become an expert on 'userChrome.css'  !)

Happy112 said

@ SinDaRella : This whole 'userChrome.css' phenomenon looks pretty daunting, I must admit - but who knows : maybe one day, when you're a bit bored, you'd like to sink your teeth in it and find that it's a actually a piece of cake ..... Would be great though if some developer would create a 'Tabs on Bottom' Webextension ....... (fingers crossed)

I wouldn't count on userChrome.css being around in its current state for very long. It may be the only way to do certain things right now that extensions have done in the past, but with the number of user complaints from inept users who can't seem to follow precise instructions about using userChrome that "we" support volunteers (and Mozilla) are seeing here, I fully expect some limits placed in Firefox as to what userChrome can modify in future Firefox versions.

"We" are recommending too many "fixes" for "restoring" real old features like "tabs on the bottom" that Mozilla killed long ago, and I feel that's gonna bite us in the butt within the next year when Mozilla says "enough is enough" and starts regulating what type of modifications that will be allowed via userChrome scripts. IMO, if the user just has to have "tabs on the bottom" that disappeared 3 1/2 years ago - my feeling is to tell them to use a different web browser that has that feature. My feeling it that these "whining" question threads promoting the user of userChrome.css for totally unqualified users will be the "straw that broke the camel's back", and "screw" those of use who have been using the triumvirate of the "user files" quite successfully for as long as Firefox has been made.

As it now stands, Firefox 58 (or 59) will have telemetry to look for the mere presence of a userChrome.css file. (per a Bugzilla report that was filed a month ago.) If Mozilla see's wide spread use that may trigger an "investigation" into how it being used. Code has already be written & submitted to "scrape" that code so the developers can see what type of mods are being done by users; and mention has been made at to what types of code might be disallowed at some future date with an unspecified version number release.

IMO, Mozilla is about to enter the 1984 Orwell zone where Big Brother is watching us too much.

Ed, it's interesting you go "Big Brother". I'm spinning up a project to investigate what new API's users want, and it's entirely possible that some of the changes in userchrome could become API's. We don't want to squash customization, we just want the browser to be great for those who customize, and the many more who don't