Hi! to make it short:

I installed Kali Linux, after post-installation's reboot the grub interface looks weird (I don't know how to post images so I'll try my best):

Maybe it looks kinda normal because of the monitor's lightness but believe me when I say it looks really bad, also the letters appear and dissapear simultaneously and, as you can see, the selector is 'invisible' making it harder to know which one is being chosen. I thought It would be some normal/weird error so I should be able to fix it with grub-customizer, but... I installed some grub template from www.gnome-look.org, I put it manually inside the "/grub/themes/" folder, the grub customizer recognizes it but when I make the changes and save when I reboot it stills looks the same.

PS: I tried to install 0.97 legacy version but it could not recognize windows OS no matter what I did, so I reinstalled grub2.

Please help.