Currently Balsamiq Cloud uses Open Sans font for the UI. It works well for Latin charsets, but makes pain displaying Cyrillic, and probably others non-latin charsets.
Open Sans doesn’t support Cyrillic, so browser applies default font-family, which is Times New Roman. This makes too hard to read small serif texts, and it looks non-accurate, see the picture:
Use Styler Classic extension to override CSS font styles. I’ve set up Verdana as a default UI font, see the settings:
I’m happy with the results: