To customize your navigation buttons, please, follow to Theme settings > General
And choose Navigation tab. You’ll get the following options’ list:
Set the buttons (items’ background) colors and their position (in pixels, from the top).
When use a Demo content, your items are set automatically like on the demo site – all the colors and positions are appropriate. However, you should first save changes in the Navigation Settings to enable the default configuration.
Follow to Theme Settings > Appearance > Fonts > Navigation
and choose the color, fontname and size for all the navigation elements: item title, hover, dropdown, dropdown hover. There’s a font line height option as well, so you can control the vertical distance between item lines. Don’t forget to save changes.