Need to change font color for single menu

well if you can investigate your menu-item number here is the code:

#menu-item-4424 .avia-menu-text {
    color: #900 !important;
}

but if the menu changes (f.e. an additional menu item is set this could be changed)

you can do it via dashboard go to menu and have a look to the top of the window ( there is an option button) please click it.
now you have the choice to blend in a css class setting by checking the box

now you have the opportunity to give each menu point a different custom class
f.e. red
now you can go to quick css and :

.red {
    color: #900 !important;
}