You should adept parts of your page for phone screen width by using @media(max-width: …) …
Yeah, didn’t even checked the mobile as test is passed and I am not a fan of working on codepen Having all windows on one screen plus opened console - not loving it.
As I am already using Bootstrap it’s “better” to just change class of the div around nav - form col-4
to col-sm-4 col-12
- done.