Zen Browser: A Minimal Firefox That Feels Like Yours

Zen Browser

I have spent years making every layer of my desktop my own, the window manager, the editor, the terminal. Yet for the longest time, the browser remained a stock rectangle I tolerated. Then I found Zen, and for the first time, the browser stopped being an exception to my customization rule.

Why Zen?

Zen is a Firefox fork with one obsession: minimalism through vertical tabs. If you use a tiling window manager, you already know the horizontal strip of tabs is wasted space. Zen moves tabs to the side, keeps the web page front and center, and gives the whole interface an airy, modern feel.

It stays close to upstream Firefox, which means the rendering engine, privacy features, and extensions all behave as expected. The magic is in the shell around them.

ZenMods: CSS as a First-Class Citizen

Zen's killer feature is ZenMods, a system that lets you install CSS-based modifications to the browser interface without hand-editing files.

I customized the interface through the ZenMods preferences UI, and Zen generated a zen-themes.css file in the profile's chrome/ directory:

/* Zen Mods - Generated by ZenMods. */
/* DO NOT EDIT THIS FILE DIRECTLY! */
/* Instead, go to the preferences and edit the mods there. */

The pattern will feel familiar to anyone who has touched userChrome.css in standard Firefox. Zen treats the browser UI as a stylesheet you can theme, collapsing sidebars, rounding corners, hiding clutter, all through the same mental model as my Hyprland and Neovim configs.

Two Profiles, One Install

Like Firefox, Zen separates profiles in ~/.config/zen. I keep a default profile for everyday browsing and a second release profile with the heavier mods. It is the same isolation principle I use everywhere else: if one experiment breaks, the other profile keeps working.

Conclusion

Zen proves that a browser does not have to be a fixed product. By exposing the interface as CSS and making vertical tabs the default, it aligns perfectly with the tiling philosophy that already governs my desktop. It is the closest thing to a window manager for the web.

If you want the full experience, install Zen, open the Mods preferences, and start treating your browser like a config file.