navigation pane rendering with Firefox

[hennion]

Dear pixeldroid,
thanks for this nice theme! I'm trying to set up a small github.io website but the rendering of the navigation pane is not nice when using Firefox (when more than 3 collections, the 1st sub element name is cut, see github.io.png). The rendering is fine (see local.png) using Firefox and local page done with jekyll serve. The github.io website is OK using Chromium or Falkon. So this is only using Github server and Firefox that I have the problem... Is there a way to avoid that? Maybe, to increase artificially the space between the collections and the sub elements? Thanks for you help!