Make section line thicker by 1px. Make extra thickness of table header row line (underline) thinner by 1px
after checking this I would propose some different variant, as IMO this would look very bad.
So couple of other proposals. I think that colorful section lines add too much noise. My favourite is with section separator made 1 px thicker (2px) and table header line 1 px thinner. WDYT?
Indeed, this does not look very good, I'm leaning towards your proposition, it seems cleaner.