On many websites, when I see wonky things like that, I increase or decrease tyhe zoom by small amounts "until I get lucky".
My theory is that, with so many different display devices and OSes and browsers, and WIDE range of screen size and resolution, there is always SOME combination that looks bad, because (probably) not every browser follows the same rules for screen display.
"Make it look good on EVERY display, including those you don't have and can't test"
is like:
"Define the Universe and give three examples."
Somewhere between very difficult and impossible.