issue with latest firefox 142 and 143

### Guidelines

- [x] I have read [how to report a new issue](https://github.com/Aris-t2/CustomCSSforFx/issues/4)
- [x] I have used the [latest release](https://github.com/Aris-t2/CustomCSSforFx/releases/latest)
- [x] I have set the `toolkit.legacyUserProfileCustomizations.stylesheets` in `about:config` to `true`

### Does the issue occur without any files inside /chrome/ folder?

Yes

### Description of the Issue

### Issue description, userChrome.css/userContent.css 'settings' the issue occurs with and steps to reproduce the issue

### Does the issue occur with the most recent version of CustomCSSforFx (release/test/dev build)?

Yes, with the latest release

### Screenshots showing the issue

pls see this image:


as you can see the folder in bookmars tab are coloured as always in yellow
but their sub-folder has no clour...
see for ex the bookmars tab folder named:CH is yellowed colour
but its subfolders: CH2, crea spartito and CT have really no colour...
how to have also them in yellow colours as for their main folder named CH?
thxs in adv
cheers

### System information

- OS & OS version: win 10 home 64
- DPI/HiDPI/scaling value, if not 100% (e.g. 125%, 150%...):
- Firefox version: 143
- Firefox theme (e.g. default, build in light/dark, external theme + link): dark

Reproduce the bookmark-folder styling issue in Firefox 143 on Windows 10 using the screenshot and the reported CustomCSSforFx setup. Start by isolating which userChrome.css or userContent.css setting controls bookmark folders; done means the CH subfolders and other nested folders receive the same yellow color as their parent folder.

Written by the indexing model from the issue text.