sub-menu display

Hello,
I recently started with a new Page I wanted to setup. I would like for the sub-menu to always be displayed (not sliding in on hover / mouse over). I could not find an option to change this nor did I find the correct files to change.

Is there a setting I’m missing?

If not: which file do I have to change? I fiddled with some css settings in the child theme but could not remove a strange hover effect.

Thank you for your reply

The page I need help with: [log in to see the link]