Case Study

Firefox Ghost UI

A floating Firefox toolbar that stays out of the way, with native vertical tabs, a download island, and an automated Windows installer.

Completed successfully CSS / userChrome.css Windows Installer Vertical Tabs

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Get the theme or inspect the source

Firefox Ghost UI is completely free and open-source. Install it in seconds via the automated Windows script, or configure it manually.

Releases & Download View on GitHub

Result

Firefox Ghost UI creates a modern, ultra-clean web browsing experience on Windows: pages get the maximum possible screen area while tabs, controls, and downloads remain instantly accessible.

Problem

Default browser interfaces take up substantial vertical screen space with static bars, tabs, and window frames, creating distraction and reducing active reading area.

Solution

Firefox Ghost UI floats the address bar as an auto-hiding overlay, introduces smooth native vertical tabs without viewport shifting, and packages everything in an automated installer.

100% Native Engine-level Gecko CSS styling, zero heavy background extension overhead.

0 Viewport Shift Floating overlay architecture means web pages never jump or reflow on hover.

1-Click Setup PowerShell script detects profiles, saves backups, and applies changes safely.

Features

Smart Floating Toolbar

Reveals on top-edge hover or Ctrl+L, allows pass-through clicks outside the center pill, and auto-collapses smoothly when done.

Hover-Expanding Vertical Tabs

Compact icon rail expands on hover over the web page without moving the page layout or forcing horizontal resize.

Isolated Download Island

Downloads live in a floating pill with native progress rings and completion animations, separate from the address bar.

How it works

Automated profile detection

Install.cmd runs with local PowerShell rights, scans AppData Firefox profiles, prompts for target selection, and creates timestamped backups.

Modular userChrome & Gecko preferences

Deploys clean CSS wrapper imports into chrome/ghost-ui/ while configuring legacy stylesheets and vertical tabs flags in user.js.

Seamless extension hooks

Out-of-the-box support for Adaptive Tab Bar Colour, reduced motion preferences, and Bonjourr start page animations.

Safe & 100% reversible

Uninstall.cmd restores original CSS and preferences instantly. Your bookmarks, browsing history, and saved logins are never touched.

Hardware accelerated

CSS transforms and opacity filters run on the GPU through Gecko, preserving battery life and rendering at high frame rates.

Technology Stack

CSS / userChrome userChrome.css and userContent.css defining the floating toolbar and layout.

PowerShell Automates profile discovery, backup creation, and preferences management.

Batch Launcher Double-click Windows launcher ensuring execution policy bypass for installer.

Gecko Engine Native Firefox engine flags enabled via user.js configuration.