On: Using hamburger menus? Try sausage links (2019)

[josho]

That's solved by adjusting the scroll starting position so that the first element is partially offscreen. It may initially look jarring, like the designer made a mistake but it provides a nice visual affordance that you can scroll and it will work regardless of the screen width.

https://codepen.io/blipo/pen/Rwxrgpd

[onion2k → josho]

Now your menu requires JS though, which isn't ideal, especially on a brochure site that could work perfectly well without it.