Our base theme Nucleus supports to implement multi-skins/colors for its sub-theme. Ex: add a blue skin
Create a new skin/color
Step 1 Open file
mytheme.info
and add line:
skins[blue] = 'Blue Style'
Step 2 Create the skins folder. Then, create a color folder with name "blue" inside the folder like below picture:

Skins Folder Structure
Step 3 The color folder could contains following files/folder:

Skin Files
- images: is a folder which contains all background images which will be used in your skin css
- logo.png: Site logo which is used for this skin.
- style.css: has all css of this skin.
Step 4 Go to your site > Configuration > Performance > Clear your Drupal cache if your site has been live.
Select a default color
Step 1 Login to your site as an admin
Step 2 Go to Appearance > Your theme settings > Layout > Select a color as a default > Save your configuration