Hello, i want to do something similar to the menu with the eurovia webpage, the logo is up, but when you scroll down on a webpage with more text the logo goes to the left of the menu ,as shown on the screenshots

This is the menu when you are on top of the website https://imgur.com/I0TZPkG and this is the menu when you scroll down the website https://imgur.com/clRBBly

I was watching and the closest template is the Finion one, who is installed on my hosting (gama.probisa.org)

Is there any way to make the menu similar to the other webpage?

On the hidden content is the login on the website.

Thanks in advance!