one of the ways, without extra codes, could be this:

you need to create a transparent gif with red and gray background for each breakpoint of appropriate size and place it in Model Structure
then create 3 menu layers (there are 3 menus not 2 as you say)
2 of which are hidden
I personally don't like it

content of template with the 3 menu

here is the result, obviously to be refined, I did it “on the fly”

your email doesn't read--however, I don't respond privately to users
I put explanatory pictures of everything you need
I add the map related to the menu since you say you didn't understand and the first GIF for desktop resolution (1150px)
I created the project in less than 5 minutes... so it is easily reproducible... sorry but i think, you'll get more satisfaction and benefit from recreating it than from copying it

...