On the main menu, the text color automatically switches between light and dark depending on the background/header color. This works fine on my PC and MacBook, but not on my iPad. On my iPad, the text is always white, so when I switch to a page with a white background, the menu is rendered invisible.
I checked with a friend who also has an iPad, and he sees the same issue.
I did a bit of investigating on this. If I go to Customize > Colors & Backgrounds, and click the Default button to use default colors, then the menu items display fine on an iPad.
However, as soon as I change the link color to #ed3237 (while leaving the default background and text colors unchanged), then menu items start displaying as white on the iPad. So the issue appears to be with the link color settings. It’s not custom CSS.