Problem: Trying to make the mobile toggle icon completely flush-left. But there is an empty space hard-coded into the plugin which prevents a float-left toggle icon from being truly flush-left.
Solution: (From the plugin moderator) There are two different ways to achieve that.
Add any of these snippets into Style Configuration -> Custom Tweaks:
Follow up: This class-based solution works.
Follow up: This id-based solution does NOT work!