Responsive Navigation in 9.1.3

Thanks for all the help from everyone. I now almost have a working site with 9.1.3, PHP 8.1 and MYSQL 8.0.
The only problem is the responsive CSS. when the screen is mobile sized instead of the three lines and the dropdown list I just get a small icon and no list. The Theme was developed a while ago using a clone of the Elemental theme. I’ve looked at the Elemental theme included with 9.1.3 but can’t see any radical difference. However my version is using Bootstrap 3.2 whilst Elemental with 9.1.3 is using 3.4.
My medium term goal is to develop a new theme based on Atomic but I first want to get a fully working version in 9.1.3 with the current theme.

Hi @DL0rnie - yeah I think that’ll be a little tough to help you with without more details about what you’re running into (realize it’s been a bit since you’ve posted). Do you have maybe some CSS examples and screenshots we can take a look at?