Who is Per-Domain User CSS for?

Per-Domain User CSS is a consumer product built for firefox users who customize website appearance.

Does Per-Domain User CSS have a free plan?

Yes — Per-Domain User CSS is free to use.

What platforms does Per-Domain User CSS run on?

Per-Domain User CSS runs on the web and embeddable surfaces.

Is Per-Domain User CSS still active?

Unverified. Per-Domain User CSS has not been re-checked since it entered the index, so there is no finding either way — and only a positive finding would say otherwise.

What are alternatives to Per-Domain User CSS?

Similar projects tracked by PulseGate include Per-Site CSS Injector, User JavaScript and CSS, and Custom CSS.

Who makes Per-Domain User CSS?

Per-Domain User CSS is developed by ArachnidFight.

How long has Per-Domain User CSS been around?

Per-Domain User CSS first shipped in 2025.

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Per-Domain User CSS

Name: Per-Domain User CSS
Author: ArachnidFight

mozilla.orgBrowser DevTools & extensions

Per-Domain User CSS is a Firefox extension for applying custom CSS to individual domains or subdomains. It provides a popup editor with preview, save, enable/disable controls, optional !important insertion, and local-only storage.

FreeWebEmbeddable

Visit mozilla.org

Overview

8 features

Per-Domain User CSS is a Browser DevTools & extensions project. It focuses on restyling websites with unreadable fonts, poor colors, or inconvenient layouts without editing each site manually. It is built as a consumer product for firefox users who customize website appearance. It is available for free. It runs on the web and embeddable surfaces.

Behind Per-Domain User CSS is ArachnidFight, and it first shipped in 2025. Among its 8 catalogued features are Per-domain CSS, subdomain styles, and style toggle. The interface is available in 32 languages, including Czech, German, and Greek.

Summary written by a language model from the project’s public pages.

Per-domain CSS
Subdomain styles
Style toggle
Live preview
CSS editor
Auto !important
Local storage
No network access

Built with & integrations

Runs on

BrowserEmbeddable

Trust & compliance

Verified signals

HTTPSPrivacy Policy Terms of ServiceFree tierMulti-languageStore-verified publisher

Legal

Indexing history

What PulseGate has recorded for this listing

Indexed16 Sep · 05:30 UTC
Per-Domain User CSS verified via Firefox Add-ons
Source: Firefox Add-ons · Open

Frequently asked questions about Per-Domain User CSS

What is Per-Domain User CSS?: Per-Domain User CSS focuses on restyling websites with unreadable fonts, poor colors, or inconvenient layouts without editing each site manually. It is catalogued under Browser DevTools & extensions on PulseGate.
Who is Per-Domain User CSS for?: Per-Domain User CSS is a consumer product built for firefox users who customize website appearance.
Does Per-Domain User CSS have a free plan?: Yes — Per-Domain User CSS is free to use.
What platforms does Per-Domain User CSS run on?: Per-Domain User CSS runs on the web and embeddable surfaces.
Is Per-Domain User CSS still active?: Unverified. Per-Domain User CSS has not been re-checked since it entered the index, so there is no finding either way — and only a positive finding would say otherwise.
What are alternatives to Per-Domain User CSS?: Similar projects tracked by PulseGate include Per-Site CSS Injector, User JavaScript and CSS, and Custom CSS.Per-Site CSS Injector User JavaScript and CSS Custom CSS
Who makes Per-Domain User CSS?: Per-Domain User CSS is developed by ArachnidFight.
How long has Per-Domain User CSS been around?: Per-Domain User CSS first shipped in 2025.

At a glance

Pricing: Free
Platforms: Web
Built for: Firefox users who customize website appearance
Model: B2C
Solves: Restyling websites with unreadable fonts, poor colors, or inconvenient layouts without editing each site manually.

Registered as

Firefox Add-ons: per-domain-user-css

Developer

ArachnidFight

Index record

Indexed: 16 Sep 2026
Lifecycle: Alive
Last seen: 16 Sep 2026

Identity audit (13)

Slug: per-domain-user-css-mozilla-org
Lifecycle state recorded: 16 Sep 2026
Verification state: Indexed for public listing
Listing state: Listed: yes
Index status: Included in index
Latest evidence snapshot: 16 Sep 2026
Timeline basis: Indexed-at chronology. This listing's first-seen date was written by the catalog backfill, not observed here, so it is not treated as a sighting.
Name from: Derived from the project's own page and URL.
Category from: Assigned by a language model.
Summary from: Written by a language model from public pages.
Languages from: Detected by a language model, checked against the page's own declaration.
Last updated: 16 Sep 2026
Canonical URL: https://addons.mozilla.org/en-US/firefox/addon/per-domain-user-css

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