Override CSS for websites without installing add-ons in Firefox! 🦊 (notion:be29f352627d4784bdc7b630e7ce473e)

.md

1. Open Firefox and press Alt to show the top menu, then click on Help → Troubleshooting Information
2. Click the Open Folder button beside the Profile Folder entry
3. Create a folder named chrome in opened directory (must be lowercase)
4. In the chrome folder, create a CSS file with the name userContent.css
5. Copy the following code to userContent.csswith changes according to your needs

   @-moz-document domain(website.com) {
       div.premium-button { display: none !important; }
   }

6. Open about:config page in Firefox
7. Find toolkit.legacyUserProfileCustomizations.stylesheets entry and change it to true
8. Restart browser and enjoy native css in Firefox!

userContent.css

/* Pocket */
@-moz-document domain(app.getpocket.com) {
    /* Upgrade button at the top ribbon. */
    a.css-osuxsv,
    /* Container with Premium advertisement under side navigation. */
    div.css-3ceer { display: none !important; }
}

/* Feedly */
@-moz-document domain(feedly.com) {
    /* Upgrade button at the top of the page. */
    #topHeaderBarFX button.pro { display: none !important; }
}