title: Change border color of material ui checkbox
body: <p>Here is my checkbox when checked:</p>
  <p><a href="https://i.stack.imgur.com/2yBRS.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/2yBRS.png" alt="enter image description here" /></a></p>
  <p>Here is my checkbox when not checked:</p>
  <p><a href="https://i.stack.imgur.com/aYBXd.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/aYBXd.png" alt="enter image description here" /></a></p>
  <p>All of the posts relating to styling the checkbox pertain to the fill color, the check color, etc.  I must be missing something obvious here - just trying to make the border dark!</p>
  <p>My code:</p>
  <pre><code>&lt;Grid item xs={12}&gt;
    &lt;FormControlLabel control={&lt;Checkbox onChange={(event) =&gt; {
      console.log(event.target.checked)
      setValue('isParty', false)
    }} /&gt;} label=&quot;Party&quot; /&gt;
  &lt;/Grid&gt;
  </code></pre>