title: How to change style of child element by root component in material UI?
body: <p>I have a component provided by material UI, When I pass my style as a classname to the component using withStyles, the entire component is styled. I would like to change the style of a child element, not the root.</p>
  
  <p>More especifically, the root component has a class called MuiTreeItem-root, and inside this div there is a class called MuiTreeItem-content. That is what I would like to override. Is it possible?</p>
  
  <p>Thanks in advance</p>