FF57+ only uses chrome css scripts now and if you don't have this installed you can't customize it.

Hi sammyfig, the Themes on the Mozilla Add-ons site are only for the toolbar area of the browser, not for the web page content. But it might be possible to use other methods to modify those.

What pages do you want to customize? For example, do you want to customize the built-in home page and new tab page? Or some other sites?

sammyfig said

I want to know if you will ever be able to customize the entire page instead of just the top part of the page, Google and other search engines let you customize the whole page to make it more beautiful but Firefox only lets you do the the top part

Just to be certain, Firefox is a web browser and not a search engine as a search engine is for example google.com, bing.com

https://support.mozilla.org/en-US/kb/add-or-remove-search-engine-firefox https://support.mozilla.org/en-US/kb/change-your-default-search-settings-firefox

WestEnd said

FF57+ only uses chrome css scripts now and if you don't have this installed you can't customize it.

You should be accurate and say userChrome.css as otherwise people may think you are referring to something related to the Google Chrome web browser.