title: Sizing the MUI CircularProgress
body: <p>I'd like to show the MUI <code>CircularProgress</code> component as big as needed to nearly fill the parent div of an unknown size. Let's say, the size should be <code>0.8 * min(parent_height, parent_width)</code>. I tried fooling with <code>max-width</code> and whatever with no success.</p>
  <p>I could use some <code>useDimension</code> hook and measure the parent's size, but I consider it to be the last resort. There must be a pure CSS solution, am I right?</p>