No Menu on Mobile?

I am experiencing two weird problems with my website. First, when I visit my website on a mobile device, the top-level menu disappears. Only the buttons on the homepage are accessible, which means, when someone clicks on a button on the homepage, they have no way to access other parts of the site (like the contact page) because there is no menu! Any thoughts on how to fix this?

Second, for some reason my slider (on the home page) doesn’t scale properly on different screens (not fully responsive). On my laptop screen, the slider size is correct width and height. On my desktop screen (which is significantly larger) the slider image shrinks in height and increases in width. And on mobile it doesn’t seem to scale at all. Is there some way I can get the image to scale proportionally?

Any help would be much appreciated! My website: https://nicolebedford.ca/