Theme ​doesn't get the code in module.less

Error: Theme doesn't get the code in module.less of modules those are not guaranteed

Solution: 

Claue theme doesn't extend from Magento Luma or Blank theme, so that's why the code in module.less is not rendered, we have listed the third party extension that the theme is compatible on theme's description. 

So now if you need to have css of extension on our theme, please copy it to MGS -> Theme Settings -> Custom Style