Configuring gvim menu font size

I am new to fvwm machine which is used by my new employers. I am struggling in customizing gvim menu (File, Edit,etc) font size. As you can see in the attached image, the font size are decent, but menu size is pretty small as compared to text font size.
It is really tough for eyes to focus on this :frowning:

How to solve this??

reference Image:

Added later: I am working on a unix machine with FVWM interface.

The gvim GUI is gtk based so you must adapt your .gtkrc in your home. How to do this see here:
ArchWiki - GTK+
Customizing GTK Apps
~/.gtkrc-2.0 Example

Hope this helps a bit.

– Thomas –