omarchy-web-retheme: your Omarchy theme on every website

A free browser extension for Chromium, Chrome, Brave and Firefox that restyles every site in your current Omarchy theme and follows when you switch. Two modes, a per-site skip, one install script.

By Mackenzie Bowes · mackenzie@mackenziebowes.com · @_mackenziebowes on X

Switch your Omarchy theme and every open tab follows, live. omarchy-web-retheme reads the theme file Omarchy already keeps, and restyles each site in Chromium, Chrome, Brave or Firefox with its colours.[1] Which of the 22 Omarchy themes keep your text readable, and which miss?

The README opens on one page in the default, Kanagawa and Catppuccin themes.

What do I get?

1. Your theme on every site. The page background, text, links and form fields take the colours of your current Omarchy theme.
2. Live switching. The extension watches ~/.local/state/omarchy/current/theme/colors.toml. When the theme changes, tabs that are already open change with it.
3. Two modes. Full mode recolours every element that has an opaque background, and leaves images, transparent overlays and brand colours alone. Soft mode changes only the page background, text, links and form controls.
4. A skip for sites that break. The popup has a per-site skip, for a site that shows state by background colour alone.
5. Text you can read. Body text and small text pass WCAG AA contrast on all 22 themes that ship with Omarchy, and links pass on 19.[2]
6. Your theme's colours in your own CSS. Every palette key becomes a variable, so bright_red is --omarchy-bright-red.
7. Fixes for big sites. X and YouTube are already in the per-site list, because both draw their icon buttons as filled boxes.[1]

What does using it look like?

You install it once. After that you do nothing: pick a theme in Omarchy, and the white pages go to that theme's background and text colour in every open tab. Pick another theme and they change again. The README opens with one page shown three ways, in the site's own colours, in kanagawa and in catppuccin.[1]

If a site looks wrong, open the extension's popup and skip that site.

How do I install it?

git clone https://github.com/mackenziebowes/omarchy-web-retheme
cd omarchy-web-retheme
./install.sh

install.sh registers the helper that reads your theme for Chromium, Chrome, Brave and Firefox. Then load the extension/ folder:

• Chromium, Chrome, Brave: open chrome://extensions, turn on Developer mode, choose Load unpacked, and pick extension/.
• Firefox: open about:debugging#/runtime/this-firefox, choose Load Temporary Add-on, and pick extension/manifest.json. Then open the popup and click Grant access to all sites once. A temporary add-on goes away when Firefox restarts.

The code is MIT licensed and has no build step, so changing a colour rule is an edit to extension/css.js and a reload.[1] Which themes keep text readable, and which miss? The contrast numbers for all 22 are in how I made every website follow my Omarchy theme.

If you run Omarchy and a site looks wrong in your theme, I'd like to hear which one: mackenzie@mackenziebowes.com or @_mackenziebowes.