How to change the style ( CSS code ) of the Customizr WordPress theme?

There a two main ways to customize the style (  CSS code ) of the  Customizr WordPress theme :
  • You can either use the Custom CSS section in the customizer panel
  • Or edit the style.css file of a child theme.

How to identify the CSS atributes to modify? Use the developer tools : press F12 in your browser and inspect the page code (see this tutorial for firebug)