Individual colour settings
In addition to global colours each theme has a number of colour setting groups. Each group has a number of individual colour settings that can be customised to change the colour of a particular element (or group of elements) on your theme.
On opening colour settings within your theme, beneath the global colours you'll see a list of colour groups.
Each group corresponds to a particular page or group of colour settings, e.g. 'announcement bar' controls the settings for the bar shown at the top of each of your theme's pages (where you can write an announcement message).
You can click into a particular group in order to view the colour settings available for it.
If you'd like to customise those colours you'll need to untick the 'use global theme colours' tick box.
You'll then be able to select a new colour for each setting.
To change a colour you can click into the coloured square and choose a new colour from the colour picker.
Alternatively you can enter a new hexadecimal colour reference into the box (indicated on the screenshot below).
When you change the colour setting you'll notice the live website preview change accordingly.
When you've made your change to the colour click the 'ok' button.
When you've finished making all your colour changes don't forget to save your changes!