Generic Installation
Go to the wanted theme and click the download button.
You should now be on the Github page for that topic.
Below you should see a guide on how to install that particular theme and a few preview pictures. Anyway, here are some common steps for all themes.
Download the theme with the big green button: "Code" >> Download.zip
Open `about:config` page.
A dialog will warn you, but ignore it, just do it press the I accept the risk! button.
Search for these:
```
toolkit.legacyUserProfileCustomizations.stylesheets
layers.acceleration.force-enabled
gfx.webrender.all
gfx.webrender.enabled
layout.css.backdrop-filter.enabled
svg.context-properties.content.enabled
Then make sure to enable them all!
```
Go to your Firefox profile.
```
Linux - $HOME/.mozilla/firefox/XXXXXXX.default-XXXXXX/.
Windows - C:\Users\<USERNAME>\AppData\Roaming\Mozilla\Firefox\Profiles\XXXXXXX.default-XXXXXX.
macOS - Users/<USERNAME>/Library/Application Support/Firefox/Profiles/XXXXXXX.default-XXXXXXX.
```
Create a folder and name it chrome, then assuming that you already have cloned this repo, just copy the theme to chrome folder.
Restart Firefox.