Moonspeaker said:
Discovered another limitation of the embedded notes in their current state: leading. In an echo of one of the snags occurring at the inception of Danbooru 2.0, text leading/line spacing appears to be fixed within a certain range. So when one uses text over a certain size in multiple lines, the letters eventually overlap. The effect is exaggerated when one uses a background color effect for text over a certain size, as the background color on one line will cover up low-hanging portions of letters on a higher line, even if the letters themselves aren't large enough to overlap directly. (Rollover text display still looks fine, of course.)
I discovered this while fancying up the text effects on post #798607 (which was originally translated long before I knew background color was even possible in translation notes), so please refer there to see what I mean.
Also, the default text centering of the embedded notes generally looks nice, but I suppose it means we'll have to insert a left-alignment tag where necessary. Well, it's a trade-off.
You could try using a div or p instead of a span and see if that works any better.
Updated