Trying to style menu item

I am trying to style a link in a menu. I used a custom-menu widget to place it on my webpage https://constructorareivax.com/proyecto-alexina-2/ At present, if you hover over each item in the menu it changes color. There is one item “Galeria de Fotos” that I would like to change, so that when you hover overn it, the color does not change but remains the same. Please note that “Galeria de Fotos” is not clickable.
“Galeria de Fotos” serves as a parent heading and contains the submenu of “Lo mejor del proyecto” and “Avance de Obra”. I understand that to style the menu I need to do it using CSS. So, I went ahead and on my appearance–>Menus Screen I activated CSS Classes .I have given the menu item “Galeria de Fotos” the menu css class of: galeria2 https://screencast.com/t/oL2AI1ghlOp . I have tried to style it in my style.css file in various different ways but can not seem to get it to work. Please help.