This is not a theme styling issue. You left necessary color fields in the theme’s options empty, disabling certain styling rules.
Only background color fields can be safely left empty, leaving other colors empty can result in invisible content elements.
Thanks for the explanation, but in the colors menu, all the colors are filled with some default value and are not Empty. And I don’t find any color option that specifically says that this color is for Input fields, etc. Can you Help please?