Crossword display issue

I'm trying to produce a crossword to reinforce memorisation of the NATO Phonetic alphabet. For some reason, the cells in which learners type answers display horribly, as small round circles (see attachment) Any suggestions for improving display, e.g. as conventional square boxes?

What theme are you using? It looks like it might be the flat blue theme but if I try that things look ok. Could you send me a link (either on here or via email) and I will take a look. If it's a bug in one of the themes I can give you some css to fix until there's a fix available for the theme.

Thanks
Fay

Hi Fay
I zoomed out and strangely though the clues were in a smaller font size, the boxes were bigger (see 2nd attachment). Maybe the problem is that I have 26 words, and that they don't fit neatly into a smallish grid!