HI @Sasha123 Couple things.. you are using a very old theme. The theme still allow for separate editing between desktop/mobile, however, these themes are no longer supported and may not receive the needed updates. You have also customized the theme by altering the html/css which could have an affect on mobile navigation.
If you update to a newer, responsive theme you will not have an issue with the mobile navigation font color. Since you are updating from an old theme I highly suggest first making a copy of the site and practice switching the theme on the copy first. Once you are confident in the changes/edits you will need to make after updating, you can switch back to the original site and make the same changes. Let me know if you have any questions. Thanks!
