Menu Fonts

I have been trying for hours to do the following:

Increase the font size of my primary and secondary menus
Change the primary menu to just have the first letter capitalized
Change the font to something more readable.

I have tried what is suggested in other posts, including using Custom CCS Manager and inserting

#menu-primary {
    font-size: 200%;
}

I have tried editing style.css under PRIMARY MENU and SECONDARY MENU, but no changes. I have tried %, em, and px.

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