title: dynamic styles in MUI sx prop?
body: <p>Is is possible to use dynamic styles in the MUI sx prop? Something like this:</p>
  <pre><code>&lt;Box
    key={index}
    sx={{
      height: &quot;100%&quot;,
      width: &quot;100%&quot;,
      {index === imgIndex &amp;&amp;
      {&quot;@keyframes fadeIn&quot;: {
          from: {
              opacity: 0,
          },
          to: {
              opacity: 1,
          },
          },
          &quot;fade-in&quot;: {
          animation: &quot;$fadeIn 2.5s&quot;,
          }}}
      }}
  &gt;
    {child}
  &lt;/Box&gt;
  </code></pre>
  <p>If not, what options are there to do something like this?</p>
  <p>My use case is this is a refactor of a carousel that was done with MUI4 (makeStyles) and I'm migrating to MUI5 (no more makeStyles)</p>