WordPress Admin Toolbar only black

Hi,
Suddenly, without doing anything, the wordpress admin toolbar disappeared.
I have tried all things I found over the internet but I cannot fix it.
The problem is in the theme but I want to fix it, since I have already put a lot of codes in this theme and I do not want to use another one.

Please, help me!

Thank you very much!

The page I need help with: [log in to see the link]