simonkahan on "[Plugin: SZ - Google for WordPress] compatibility with customizr"

I am using the customizr theme which nicely rearranges components as the browser window is resized all the way down to a mobile device.
I have tried using this plugin to display a google group forum using the shortcode.
It works great until the browser window is small, such as on mobile: then the iframe for the forum runs too wide. On a browser window, some of the button menus are inaccessible. On mobile, they are accessible but only by scrolling off to the side.
What can I do to change this so that the page just fills the visible space?
Thanks!

https://wordpress.org/plugins/sz-google/