Features & Capabilities
User Growth & Download Statistics
- By:
- Kenny Ooi
- Daily users:
- 716 13
- Rating:
- 4.17 (6)
- Version:
- 1.1 Last updated: 2022-01-12
- Version code:
- 5347695
- Creation date:
- 2022-01-11
- Risk:
- High risk impact Low risk likelihood
- Permissions:
- Content scripts matches:
- *
- *
- Size:
- 27.12KB
- Email:
- ke*****@qutebox.com
- Full description:
- See detailed description
- Source:
- Firefox Add-ons Store
- Data ingested on:
- 2026-06-21
- Compare stats and ranking:
-
Contact the developer
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User Reviews
by De*****, 2025-10-01
It is a lifesaver, a few css commands and YT is usable.
by wn*****, 2025-07-19
Awesome - this works reliably and does not spy on me like stylus and stylish do. I would love to see it expanded to manage styles by url in the future, that's why only four stars ;)
by ma*****, 2025-02-11
Is Custom CSS Safe?
Risk impact
Risk impact measures the level of extra permissions an extension has access to. A low risk impact extension cannot do much harms, whereas a high risk impact extension can do a lot of damage like stealing your password, bypassing your security settings, and accessing your personal data. High risk impact extensions are not necessarily malicious. However, if they do turn malicious, they can be very harmful.
Custom CSS requires some sensitive permissions that could impact your browser and data security. Exercise caution before installing.
Risk impact analysis details
- Critical Grants access to browser tabs, which can be used to track user browsing habits and history, presenting a privacy concern.
- Critical ****** ****** ** *** ********* ****** * *********** ******** **** ** ** *** ******* *** ****** **** **** *** ******* *****
- High ******* ******* **** *** ****** ***** *** ***** ** ******* **** ********* ********* ** * *********** *****
Risk likelihood
Risk likelihood measures the probability that a Firefox add-on may turn malicious. This is determined by the publisher and the Firefox add-on reputation on Firefox Add-ons Store, the amount of time the Firefox add-on has been around, and other signals about the Firefox add-on. Our algorithms are not perfect, and are subject to change as we discover new ways to detect malicious extensions. We recommend that you always exercise caution when installing a Firefox add-on.
Custom CSS has earned a fairly good reputation and likely can be trusted.
Risk likelihood analysis details
- High This extension has low user count. Unpopular extensions may not be stable or safe.
- Low **** ********* *** ******* **** **** * ****** **** ***** ******** *** **** ****** ** ** ****** *** *****
- Low **** ********* *** ***** **** **** * ****** **** ***** ********** *** **** ****** ** ** ****** *** *****
- Good **** ********* *** **** **** *******
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