Since a better addon "Stylus" exists, this legacy "Stylish" version is only giving away your complete browsing history to a commercial and dubious 3rd party in exchange for sweets.

At first sight, it might conform to Mozilla's "no surprises" policy as the little cartoon doggie clearly begs for all urls. But it's not necessary, and the comfy link to userstyles is obviously just for grabbing your privcate data. Proof ist that there seems to be no way to manually check only for sites you actually would like a style for.

A lot of users will still use it because it's a well-known name and has been reviewed a lot in the good ol' days. Mozilla has a real problem with addons changing their policy for the worse. Avoid at all costs and use the alternative addon Stylus.

Spyware.

UPDATE: Do NOT use this extension. After some research into this application and monitoring the traffic it passes, I have come to the conclusion that this app is essentially spyware. It logs an inordinate unneeded amount of personal and identifiable information on your browsing habits and then sends them back to the parent company who based on investigations, is likely selling that data to any willing 3rd party. More so, the companies security of this data is largely in question. So even if they werent selling it, they arent doing much to protect it and as a result, its only a matter of time until its stolen, or we are made aware that its been stolen.

This extension is nice, but it will randomly just lose all of its settings. I was using the app for a few days in a very controlled development environment and was shocked to find that randomly one day my custom styles were completely gone and the app acted as though i was using a brand new fresh install of the add on. To make matters more insulting, when i reached out to support about it, their answer was entirely unhelpful and their response was along the lines of "it wasn't our fault, we cant help you, not our problem". This is most rude and unfortunately and as a result I will not be using this product any more and would recommend if you have any requirement for even the slightest bit of reliability that you also forgo the use of this horribly made, poorly supported application.

Having used Stylish for years, I was very surprised to see that the new version casually asks if you'd like to send *all* of your browsing information to Stylish. Duh. No. But then, when I went to simply use Stylish, the menu now shows a big picture of a crying kitten, yes, literally, telling me I didn't enable it correctly and asking me to please, please do it. What the heck!? Why am I being badgered to give up my privacy? This is just weird.

[UPDATE: A quick Google shows me that some company *bought* Stylish and is trying to monetize it by spying on everyone who had trusted the previous owners. This is despicable. Mozilla ought not allow ownership of an add-on to be transfered without a big warning on the add-on and automatic updates should be disabled. I'm switching to Stylus which respects my privacy: it collects no data about me because there's no reason for a theme add-on like this to do so.]

making the web better!

好用极了

Now contains spyware.
Get Stylus instead

Now contains spyware.
Get Stylus instead.

Now contains spyware.

non funziona più, anche se mantengo la stessa versione di firefox, mi dice di installare, lo installa, ma non funziona

Great!

Now contains spyware.
Get Stylus instead.

Now contains spyware.
Get Stylus instead.

Cool

This add-ons WAS once one of the best, meanwhile it is part of the dark side!
For details see here:
https://robertheaton.com/2018/07/02/stylish-browser-extension-steals-your-internet-history/

Das AddOn war mal eines der Besten, mittlerweile ist es Teil der dunklen Seite!
Mehr Details siehe Link oben (engl.!).