You can edit various colours associated with your chosen tempalte. To change a colour, such as the background or a tab bar colour, follow these steps.
Click on the Site Colours tab in the Templates section.
If you know the exact HEX colour you wish to use, enter it into the appropriate box, otherwise you can use the colour picker by clicking in the coloured box.
Once you have chosen your colour, click save.
Goto your shop front and refresh the page. You now should see the new colour.
Watch the video