Menu error

Hi there.
I work at this website blog : https://www.calala.org. We are a women association in Spain.
The thing is that the menu has an error, and we can not read the submenu options.

You can see an example here: https://www.dropbox.com/s/iacxh34hey2aesc/menu_error.png

The admin person is “missing” and I have to manage with the wordpress issues.
I have some knowledge of css and html but I can’t solve the problem.

Can anyone help me!!???

Many thanks