README.org

December 23, 2025 · View on GitHub

Lepton (old name: Proton Fix) :PROPERTIES: :TOC: :include all :END:

Table of Contents :CONTENTS:

[[#lepton-old-name-proton-fix][Lepton (old name: Proton Fix)]]
- [[#introduction][Introduction]]
- [[#installation-guide][Installation Guide]]
- [[#why-proton][WHY Proton?]]
- [[#why-not-proton][WHY Not Proton?]]
- [[#padding-comparisons][Padding Comparisons]]
- [[#sponsors--contributors][Sponsors & Contributors]]
- [[#bug--questions][Bug / Questions?]]
- [[#faq][FAQ]] :END:

🔔🔔 Does the theme not work after installation?

You should copy [[./user.js][ ~~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 [[./docs/Restrictions.md#supports][technical limitations]] and require a restart.

Some settings [[https://github.com/black7375/Firefox-UI-Fix/wiki/Options#using-userjs][can be conflicted]] and should be explicitly set to =false=.

🔔🔔 Is your Firefox version =v102= or lower?

You [[https://github.com/black7375/Firefox-UI-Fix/wiki/Compatibility-Issues-Solution#accent-color-at-v102-or-lower][have to set]] =userChrome.compatibility.accent_color= to =true= additionally.

** Introduction [[https://wiki.mozilla.org/Firefox/Proton][Proton]] is Firefox's [[https://acorn.firefox.com/][new design]], starting from Firefox 89. \ [[https://firefoxux.github.io/photon/][Photon]] is the old design of Firefox which was used until version 88.

Proton's [[#why-proton][overall feel is good]], but there were a few things I [[#why-not-proton][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!! | Wiki | | | | | | | | [[https://github.com/black7375/Firefox-UI-Fix/wiki/Installation-Guide][Installation Guide]] | [[https://github.com/black7375/Firefox-UI-Fix/wiki/Screenshots][Screenshots]] | [[https://github.com/black7375/Firefox-UI-Fix/wiki/Tutorial][Tutorial]] | [[https://github.com/black7375/Firefox-UI-Fix/wiki/Options][Options]] | [[https://github.com/black7375/Firefox-UI-Fix/wiki/Compatibility-Issues-Solution][Compatibility Issues Solution]] | [[https://github.com/black7375/Firefox-UI-Fix/wiki/Tips][Tips]] | [[https://github.com/black7375/Firefox-UI-Fix/wiki/Show-Off-Your-Config][Show Off Your Config]] |

[[https://user-images.githubusercontent.com/25581533/119774062-20942280-beb1-11eb-80aa-c18dd52f18d7.png]]

(Lepton's design :arrow_up:)

@@html:

@@@@html:

@@ Feature List (Click) @@html:

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

@@html:

** Installation Guide

Installation script (experimental)

Linux/Mac users: #+BEGIN_SRC bash bash -c "$(curl -fsSL https://raw.githubusercontent.com/black7375/Firefox-UI-Fix/master/install.sh)" #+END_SRC

Windows users: Run with powershell ([[https://github.com/black7375/Firefox-UI-Fix/wiki/Compatibility-Issues-Solution#windows-7-powershell-script-not-works][Does not work at Win7?]]) #+BEGIN_SRC powershell 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" #+END_SRC

Manual Installation

You can see the [[https://github.com/black7375/Firefox-UI-Fix/wiki/Installation-Guide][installation guide]] with screenshots on the wiki.

Download files
- Click the green ":arrow_down: Code" button above
- Select ":package: Download ZIP"
Find your profile directory
- Open =about:support= in a new tab
- Find the =Profile Directory(Linux)= / =Profile Folder(Windows)= entry
- Click the =Open Directory(Linux)= / =Open Folder(Windows)= button
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
Restart Firefox
- Click the =Clear startup cache…= at the top of =about:support=