While creating and updating the overall look of your website in Google Sites you will notice there are some design limitations. Here a couple quick tips to give you more design control.
In the Insert Menu you will find the layouts section. This relatively new tool will easily provide layout options for your sites.
Customize Theme Color
When accessing the Theme Menu, click on the color menu or select the last color and you can customize an exact hex color.
Not a Fan of Background Color? 2 Options to Customize
Sites works in horizontal segments and when hovering over each segment you will see 3 buttons: color palette, copy, delete. When selecting the color palette you can choose the section style from your theme, however this is limiting. Here are 3 options to take control of this look.
Image Option 1: select an image from the shared gallery. This works but may not full-fill you desired result.
Image Solid Color Option 2: Google image search a solid color (remember to filter search label for reuse). Next right-click and select “copy image address”. Add this url when selecting your image by url.