Main-Nav.css - I cannot change the hover color of the nav menu items

I have tried for the life of me to change the hover color from both the upfront menu which lets be honest needs a hell of alot more work

I have clicked on the element setting to edit the CSS for Main-Nav via the browser (The CSS window that pops up on the bottom of the page)

The save button to the right which should save all the CSS changes will not save, its like its not programed to do anything.

So no changes are saved.

I have tried this on Chrome and Safari on both my Mac and Windows Machines, no difference.

I then went into Main-Nav.css and manually changed all the settings to what I wanted, I have saved it and even now the old ugly green color shows up when I hover over the menu item.

How is this possible and what else can be done.

I have pasted the Main-Nav.CSS below

The default color I'm trying to change is [background: #4f7e7d;]
I have changed all the instances of it to [background: #DA0429;]

yet the #4f7e7d; color is what loads, yet that color no longer exists in the > Main-Nav.css

I would really appreciate some help here, and a better tutorial on how what each color swatch represent with the UPFRONT edit panel with respect to theme colors would be very helpful

Thanks

I would include a screencast of the issue but I obviously cant