sidebar and urlbar: size (icons and width) customization's?

[dashingdon]

Is there a way to reduce the size of the icons and the width of the urlbar / sidebar?  I would prefer a smaller icon size and width to optimize space.

PS: I have attempted the CSS mod approach, but it was never successful for me. Maybe someone can guide me in the right direction?

For comparison, below are the screenshots from the current configuration between Zen and Vivaldi.

thank you.

• zen browser

• vivaldi

[Seigiard]

You can use custom CSS file and edit firefox/zen UI using css

#1923
https://www.reddit.com/r/FirefoxCSS/comments/vpg9k9/how_do_i_edit_firefoxs_ui/