sidebar widget titles cut off or overlapping

Hello:
I LOVE the Sparkling theme! I’m having trouble with my sidebar– the widgets seem to be overlapping. I tried suggestions from several prior threads to reduce the font size of the widget titles, but it didn’t work — the white space cuts off the top of the next title regardless of text size.
https://chronicsickdays.com/

When I preview the layout from Admin it looks fine, but not when I open the site on my phone or tablet. It seems like the white border below each widget is overlapping the top of the next one, which cuts off the top of the title. Hopefully you can help me out. Thanks!