Question

It seems like the symbol + in the custom css is automatically replaced by a space. For example, if I add the custom css

h1 + h2 { margin-top: -5mm }

(so that extra space is removed from any h2 that immediately follows an h1), it is changed into

h1   h2 { margin-top: -5mm }

so it doesn't work.

Answer 1

Confirmed. The adjacent sibling selector (+) is replaced with a space (' ') within the editor (and the published CSS). The other selector types seem to work fine.

Answer 2

I've opened a case to look into it (FC1853909)

Answer 3

Sounds like this will be fixed on Monday 3/1. See the latest post on the StackExchange blog.