I respect proton UI and aim to improve it.
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
Go to file
alstjr7375 7f70d06b80
Fix: Bookmark Popup Menu - Compatibility #715
4 days ago
.github Fix: CI - `::set-output` to `$GITHUB_OUTPUT` 2 months ago
__tests__ Fix: Icons - Win Native Menu Active Color #650 3 months ago
css Fix: Icons - Floorp icons #710 4 days ago
docs Doc: Restrictions - Mac's menu, `-moz-box` layout, floorp supports #699 #670 #710 5 days ago
icons Fix: Icons - Global menu's new device FFv115 #716 5 days ago
src Fix: Icons - Floorp icons #710 4 days ago
.gitattributes Clean: GitHub - Mark `/css/*` as generated 4 months ago
.gitignore Add: gitignore 9 months ago
.prettierignore fix typos 8 months ago
.prettierrc.json Add: Coding Style - Prettier files #182 2 years ago
CODE_OF_CONDUCT.md Doc: Create CODE_OF_CONDUCT.md 2 years ago
CONTRIBUTING.md fix typos 8 months ago
CREDITS Doc: CREDITS - Upadate sponsors 1 month ago
LEPTON Merge branch 'master' into photon-style 2 years ago
LICENSE Doc: License 2 years ago
README.org Doc: CREDITS - Upadate sponsors 1 month ago
install.ps1 fix typos 8 months ago
install.sh fix typos 8 months ago
package.json Feature: Ver 7.0.0 5 months ago
user.js Add: Rounding - Square toolbar #677 2 months ago
userChrome.css Fix: Bookmark Popup Menu - Compatibility #715 4 days ago
userContent.css Fix: Replace userChrome and userContent with stubs which import lepton 1 year ago
waterfox.sh Fix: icon path 1 year ago
yarn.lock Build(deps): Bump json5 from 2.2.1 to 2.2.2 5 months ago


Lepton (old name: Proton Fix)

Table of Contents

Does the theme not work after installation?

You should copy user.js file before the theme works.

The option system depends on user configuration, and nothing applies without settings.
Also, real-time changes are difficult because of technical limitations and require a restart.

Some settings can be conflicted and should be explicitly set to false.

Is your Firefox version v102 or lower?

You have to set userChrome.compatibility.accent_color to true additionally.


Proton is Firefox's new design, starting from Firefox 89.
Photon is the old design of Firefox which was used until version 88.

Proton's overall feel is good, but there were a few things I didn't like and wanted to improve.
That's why this project was born, and Lepton to denote light theme layer.

Disclaimer: It works on Firefox 89 and above!!

Installation Guide Screenshots Tutorial Options Compatibility Issues Solution Tips Show Off Your Config


(Lepton's design 漎儭)

Feature List (Click)

  • Color

    • Default light/dark theme contrast enhancement
    • Colorful context menu
    • More dark mode support
    • Windows/Mac/Linux system theme support
    • Windows 7 compatibility
  • Icons

    • Panel
    • Context Menu
    • Global Menu
    • Library's open context
    • Video Player
  • Padding Narrower

    • Tab
    • Panel
    • Menu
    • Density
    • Others
  • Tab Bar Layouts

    • Tabs on Bottom
    • One Liner
    • Vertical Tab Support
  • Tab Design

    • General:

      • Connect with toolbar (buttons like tabs)
    • Selected:

      • Box Shadow: Highlight the selected tab
      • Bottom Rounding: Natural
    • MultiSelected

      • Adjust Color: Easily recognizable
    • Unselect:

      • Divide Line: React to hover like chrome
    • Unloaded:

      • Dimmed: Looks like inactive
    • Clipped:

      • Clearer Text: Adjusted clipped gradation
      • Closed Button: Visible on hover
    • Sound:

      • Remove Second Label
      • Show Favicon: Always show favicon
      • PIP Icon
    • Container Tab:

      • Highlight line position: Displayed under tab
  • Button Design

    • New tab: Looks like tab
  • Activity Stream Design

    • Search Bar:

      • Focused Shadow: Same as the accent color
      • Hand off to Awesomebar
    • Icons:

      • Size: Fill (Changes dynamically to your size)
  • Error Page Design

    • Illustrations: Restore error page illustrations
  • Video Player

    • Background Style
    • Size at fullscreen
  • Fullscreen

    • Overlap mode
  • Others

    • Animations
    • Hidden & Auto Hide
    • Activate calculator at address bar
    • Mouse pointer for each context

Installation Guide

Installation script (experimental)

Linux/Mac users:

bash -c "$(curl -fsSL https://raw.githubusercontent.com/black7375/Firefox-UI-Fix/master/install.sh)"

Windows users: Run with powershell (Does not work at Win7?)

Powershell -c "Set-ExecutionPolicy Bypass -Scope Process -Force; [System.Net.ServicePointManager]::SecurityProtocol = [System.Net.ServicePointManager]::SecurityProtocol -bor 3072; iwr https://raw.githubusercontent.com/black7375/Firefox-UI-Fix/master/install.ps1 -useb | iex"

Manual Installation

You can see the installation guide with screenshots on the wiki.

  1. Download files

    • Click the green "漎儭 Code" button above
    • Select " Download ZIP"
  2. Find your profile directory

    • Open about:support in a new tab
    • Find the Profile Folder entry and click the Open Folder button
  3. Copy downloaded files

    • Extract the downloaded zip file
    • Copy the user.js file to the previously opened profile directory
    • Create a new directory inside your profile directory called chrome
    • Copy the remaining files from the extracted zip-file into previously created the chrome directory
  4. Restart Firefox

    • Click the Clear startup cache at the top of about:support

If you prefer Photon, see Lepton's photon-style.
If you prefer Proton, see Lepton's proton-style.

WHY Proton?

I think a lot has improved.


(Proton's design 漎儭)

  • Neatly organized menu
  • Icon beautiful enough to remind you of Edge
  • Nice color scheme
  • Satisfied Rounding
  • Modal window & Scrollbar!!

WHY Not Proton?

However, there are also many flaws.


(Photon's design 漎儭)

  • Is it a tab or a button?
  • Where are the menu icons?
  • Icons in ActivityStream are too small
  • Padding gaps are wide
  • Address bar 3-point menu, screenshot moves to toolbar (can't fix)

Padding Comparisons

https://user-images.githubusercontent.com/25581533/120262626-8c97d180-c289-11eb-87a6-68e285d6d77c.png https://user-images.githubusercontent.com/25581533/120253257-6ae11f00-c276-11eb-93cf-393f9845f30b.png https://user-images.githubusercontent.com/25581533/118402352-1e33fc00-b659-11eb-89fc-3cb38207fe39.png https://user-images.githubusercontent.com/25581533/124066951-0eb21c00-da29-11eb-9ac4-c6b82a268c6f.png

  • Photon (Quantum)
  • Proton
  • Lepton

Sponsors & Contributors

Thanks to all sponsors & contributors to this project for providing help and developing features!


<img src=" title="https://user-images.githubusercontent.com/25581533/203210367-9f2eed69-666a-4218-acde-128892aa09d8.png" /> "> "> "> "> ">



A list of all contributors can be found in CREDITS.

Bug / Questions?

If you found a bug, please contact issue.
If you have any questions or inquiries, please contact discussions.


  • Black pixels around the selected tab bottom corners

Please follow the Installation Guide,
or set about:config's svg.context-properties.content.enabled to true .

  • The closed button and some panel menu icons are not visible.
    https://user-images.githubusercontent.com/77958663/130395848-7af58241-bbbf-4273-bb62-14382c44098d.png https://user-images.githubusercontent.com/25581533/120487528-93b40200-c3a5-11eb-98ad-3498beb9f38e.png

Please follow the Installation Guide,
or copy the icons directory to chrome .

  • *Less icons in the panel with photon-style*
    https://user-images.githubusercontent.com/25581533/123761424-5746c980-d8b1-11eb-9a0f-83fb305f9f08.png https://user-images.githubusercontent.com/25581533/123762962-d4bf0980-d8b2-11eb-8492-d497d330c72a.png I didn't put all the icons like before.