I built a simple website for my business in w3.css from w3schools.com; https://www.housewashingdelmarva.com/
However, when the website is reduced to mobile phone size and the navigation goes to the 3 stacked bars, I can't get it to click and lower the menu. I believe it's a javascript issue. But I am mostly a front-end CSS and HTML designer. Not sure what I have mistakenly done wrong as I have built two other similar sites that work fine mobile-wise and can't see the difference in the code.
If any javascript coders or w3.css designers notice my mistake, I would appreciate your help.
Thx!