An interesting feature is dynamic updating of dependent variable properties:

  This example shows a variable property safely using a variable:
  
  :root {
  	var-main-color: #c06;
  	var-accent-background: linear-gradient(to top, var(main-color), white);
  }
  
  The ‘var-accent-background’ property will automatically
  update when the ‘var-main-color’ property is changed.

edit: clarified the wording of this comment to remove ambiguity (not a question).