Why multiple choice ticks suddenly not showing on my forms?

Hi there

My forms have been working fine for a long time with no problems. However since the last few days, in my multiple choice form elements, you can no longer see (or tick) the boxes next to the options. The options are still appearing but the boxes next to them are not.

Is this something I have done in the settings (although I haven't made any changes recently so not sure why it's happened suddenly)?

Or is there a glitch?

Thank you 

That's because the checkboxes are white, and also the form page. So they are not visible.

You can change that by going to Custom CSS Field:

And on line 181, change color from #FFF to black:

That will resolve the problem:

Let us know if you have any further questions.

Thank you!