Using a CSS environment variable to better space a footer menu.

When viewed on an iPhone without a home button ('X' or newer), there is additional padding at the bottom to account for the 'bar' shown by iOS to indicate you can swipe up to get to the home screen. There is plenty of empty space below, so scroll down to hide the menu bars and see the difference.

Environment variable value:

Read more: CSS environment variables.

Right click and view source to see the CSS.