To define the Menu icon and Expanded Panel, please go to Air Theme > Theme Options > Header.
You could set the menu icon style, size, and spacing.
You could define the icon size by the icon height option. Please enter the integer number. It will be shown by the default size if they are empty. The default for Desktop is 26, for Mobile is 16.
The expanded panel will be shown when menu icon is clicked.
There are the options for spacing of menu items and align.
Enable Index number
The layout looks like:
The “Index number” is only available for the 4 header layouts:
If you want to define the color(Background color and element color) for the Expanded panel, please go to Theme Options > Colors: Expanded Panel