# Customizer

> Add custom CSS to one or many sites

Canonical page: [https://chrome-stats.com/d/customizer-by-robustus](https://chrome-stats.com/d/customizer-by-robustus)

## Overview

- **ID:** `customizer-by-robustus`
- **Platform:** Firefox
- **Type:** Firefox add-on
- **Status:** Available
- **Publisher:** Robustus
- **Category:** web-development,appearance
- **Version:** 4.1
- **Last updated:** 2026-07-08
- **First published:** 2026-05-21
- **Size:** 174 KB
- **Data as of:** 2026-09-14
- **Store listing:** [Firefox Add-ons Store](https://addons.mozilla.org/firefox/addon/customizer-by-robustus/)

## Description

Sometimes websites don't look the way you want them to. Simplify or change them with Cascading Style Sheets. CSS can be applied to many pages with the * wildcard. It is applied before the HTML loads. The CSS is edited in a popup window or the big options page, not in a sidebar of the page; you are not hindered by the page.

Features:
 • Edit CSS: View & edit styling for one page or many
 • Storage Sync: Options saved for use on any computer

Instructions: Configure Keyboard Shortcut:
1. Click the icon for this extension
2. Click "Keyboard shortcuts"
3. Make a keyboard shortcut for "Big options page: edit site"
4. In the future, use this shortcut so you can use "Inspect Element"

Instructions: Add Site:
1. Open the popup or big options page
2. Go to the field "Add site"
3. Type in a URL like the following
 • Normal: <a href="https://prod.outgoing.prod.webservices.mozgcp.net/v1/948443f3b4ea035581e5e0fb6695f358fececdc3e4270a0428bf6e850f144fb0/http%3A//en.wikipedia.org" rel="nofollow">en.wikipedia.org</a>
 • Wildcard: *.wikipedia.org or *
4. Hit enter or click the plus button

Instructions: Edit CSS
1. Open the popup or big options page
2. Add rules and change properties
3. Refresh the site

## Rankings

- #134,007 — Overall
- #216 — customize

## Permissions and access

### Permissions

- `tabs`
- `storage`

### Content script matches

- `<all_urls>`

## Safety

- **Risk impact:** High risk impact
- **Risk likelihood:** High risk likelihood

### Analysis details

- Grants access to browser tabs, which can be used to track user browsing habits and history, presenting a privacy concern.
- This extension has low user count. Unpopular extensions may not be stable or safe.

> Some risk analysis details are omitted from this free response. [Upgrade to view the full analysis](https://chrome-stats.com/pricing).

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Source: [Chrome-Stats](https://chrome-stats.com/d/customizer-by-robustus)