Font problems in the application Brackets

I have some problems with fonts in the program Brackets(for web development).

When I run a command from the command line I get this error:

 bohdan@bohdan:~$ brackets 
 [0426/163240:ERROR:browser_main_loop.cc(261)] Gtk: Locale not supported by C library.
 Using the fallback 'C' locale.

Fonts are broken into the program. It doesn't look readable.

I was looking for a solution to my problem on the internet, but I didn't find anything normal. Please help me.