To edit your colors, go to Appearance > Customize > Colors. By default, the colors will be the same as the demo.
The site header is transparent by default, meaning that the page header area goes all the way to the top of the page. If you would like, you can set the header to “white”. You will have to save and refresh your browser in order to see the changes. If you change this setting, the page header will start after the site title.
You can change the primary and accent colors to a color of your choice, using the color picker.
The Page Header area will default to the color of the primary color. If you would like to choose a different color for the page header, you can select it at the bottom and it will override the primary color.