If you compare the three pages below, you will notice that one manu has a blue field as the background colors while the others do not.
How is this controlled? I wish for them all to have the blue backgrownd.
The header color palette is managed on two levels.
1. Defaults (in Theme Options)
2. Overrides (on per page basis)
This system of overwriting Header default color palette comes in handy especially when you want to use the transparent header feature. In which case sometimes it is better to change the colors for better readability (ie: to use dark text over light images and vice versa).
So If you want to use Light Header text on all (or most) pages:
1. In Theme Options -> Header & Menu -> Navigation settings set the Navigation Colors to "Light text on dark background":
This will set defaults for all new pages to use this color palette. You can further customize the colors under "Navigation Colors" if needed.
2. If the settings on existig pages are not set to use default color palette, you might need to edit them and make sure the Header text color setting (below the content) is set to "Default" (or Light text):
I hope this helps,