As to why I'm asking: if you set the sidebarspace to display:none in css for mobile, it really helps the layout shift report, but then the expander is backwards +/-, so need to figure that out.

On the second question, if I change the flex order, I'm wondering if I can use the same mechanism that adds the second-copy to the class on mobile to move the Filter up to the top despite the changed flex order of the left aside.

If I could get those two things working, it could be a 16% increase in lighthouse performance on mobile.