The icon is invisible with the dark theme

[jp-insitaction]

Hi,

I'm using version 1.2.1resigned1 with Firefox 133.0 (64 bits) on Ubuntu 20.04.6 LTS and the icon is barely visible with the dark theme :(

I don't see any option to toggle the icon for the dark theme, am I missing something?
Is it possible to add this option?

Thanks.