Unicode characters in code blocks or pre not monospaced

I use Monodraw (an app) to create ascii diagrams. "ascii" is a misnomer since I do it in unicode. Unicode ascii diagrams/art aren't spaced properly. They display properly in PyCharm (for example) and in every text editor I've come across. They also display properly in Gitlab (and it's variants). Bitbucket is the only place I can't use my diagrams.