Custom CSS
Overwrite or inject custom CSS into website.
Custom CSS - Customize website styling
Custom CSS is a Firefox add-on that allows web developers and CSS experts to inject their own styles into any website, effectively customizing its appearance and overriding default styling.
Add-on stats
By: Kenny Ooi
Creation date: 2022-01-11
Weekly download count: 23
Firefox on Android: No
Risk impact: High risk impact 
Risk likelihood:
Manifest version: 2
Permissions:
- tabs
- storage
- http://*/
- https://*/
Size: 27.77K
Email: ke*****@qutebox.com
Ranking
Other platforms
Not available on Chrome
Not available on Android
Not available on Edge
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Add-on summary
A simple plugin which allow web developer or those who familiar with CSS to inject own custom CSS into any website to overwrite default styling, such as font-size, font-color, and so on.
User reviews
¡SÚPER limpia e intuitiva... me gusta cambiar la letra de las páginas, pero necesitaba un cambio específico no universal en la configuración del navegador.
// LA PANACEA:
* {font-family: Fira Mono;}
MIL GRACIAS!
by Colchón Amarrado, 2024-12-18
One of the must haves if you take browsing seriously. My wikipedia.org customizing
.mw-body-content p {
text-align: justify;
hyphens: auto;
max-width: 70ch;
text-wrap: pretty;
}
by Joe, 2024-12-04
Throws all kinds of errors for no reason, even with basic elements like #header.
It doesn't have any formatting aids either, though I suppose if all you care about is size that's not a dealbreaker.
by Firefox user 17681028, 2022-12-04
Add-on safety
Risk impact
Custom CSS requires some sensitive permissions that could impact your browser and data security. Exercise caution before installing.
Risk likelihood
Custom CSS has earned a fairly good reputation and likely can be trusted.
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