Hi there!
I’ve just switched from another Google Reviews plugin, and I like yours.
There’s an issue I’ve noticed: attribute tabindex="0" on <span class="wp-google-text"
That’s why .wp-google-text gets focus every time during keyboard navigation.
I think it’s better to relay on browser’s behavior — when .wp-google-text overflows and needs vertical scrolling (which is set on .wp-google-text‘s parent element), then keyboard navigation allows us to focus there, and scroll the text in more elegant way, only when it’s really needed.
Regards!