A Chrome extension that transforms Google Gemini into a personalized, premium dark experience.
Custom backgrounds · Floating sidebar · Per-zone darkness control · Canvas-compatible
This extension overhauls the look and feel of Google Gemini without touching any functionality. Everything Gemini does still works as normal - you just get a much nicer interface on top.
- Custom Background Images - Upload your own wallpapers for the main background, sidebar, input field, and message bubbles
- Per-Zone Darkness Sliders - Fine-tune how dark the overlay is on each zone so your images look just right
- Floating Sidebar - The left sidebar becomes a rounded, elevated panel with a soft shadow
- Premium Dark Theme - Menus, dropdowns, chips, and buttons all get a cohesive dark treatment
- Canvas Compatible - Works correctly when Gemini's Canvas panel is open
| Browser | Support |
|---|---|
| Google Chrome | Full support |
| Microsoft Edge | Full support (Chromium-based) |
| Brave, Vivaldi, Opera | Compatible via Chrome extension sideloading |
| Other Chromium browsers | Should work (Ungoogled-Chromium, Yandex, etc.) |
| Firefox | Not compatible (different extension API) |
| Safari | Not compatible |
Since this extension is not on the Chrome Web Store, you install it manually.
1. Download
git clone https://github.com/Leonxlnx/gemini-extension.gitOr click the green Code button on GitHub, then Download ZIP and unzip.
2. Load in Chrome
- Open
chrome://extensions - Enable Developer mode (top-right toggle)
- Click Load unpacked
- Select the
gemini-extensionfolder
3. Open Gemini
Navigate to gemini.google.com - the redesign applies automatically.
Click the extension icon in your toolbar to open the settings popup.
| Setting | Description |
|---|---|
| Master Toggle | Turn all custom backgrounds on or off |
| Background | Upload an image for the main page background |
| Sidebar | Upload an image for the left sidebar |
| Input Field | Upload an image for the chat input area |
| Messages | Upload an image for your sent message bubbles |
| Darkness Sliders | Adjust the dark overlay per zone (0% = full image, 80% = very dark) |
Tips:
- Use high-resolution images (1920x1080 or larger) for best results.
- Dark, moody wallpapers work well with the dark UI theme.
- Vertical images work best for the narrow sidebar panel.
content.css is injected at document_start and applies all visual restyling before the page renders.
content.js runs at document_idle, loads custom images from chrome.storage.local, applies them as CSS background images with per-zone darkness overlays, and uses a MutationObserver to re-apply styles when Gemini updates the DOM.
popup.js handles the settings UI. Uploaded images are resized, converted to WebP, and stored in local storage.
git pull origin mainThen go to chrome://extensions, click the refresh icon on the extension card, and reload any open Gemini tabs.
Contributions are welcome.
- Fork this repository
- Create a feature branch:
git checkout -b feature/my-feature - Test with the sidebar open/closed and Canvas open/closed
- Commit with a descriptive message:
git commit -m "feat: description" - Push and open a Pull Request
- Gemini updates may break styling. Google can change the DOM at any time. If something looks off, please open an issue.
- Storage quota. Chrome's
storage.localhas a ~10 MB limit. The extension automatically resizes uploads to stay within limits.
Made by Leon · x.com/lexnlin