title: React overriding child element styles
body: <p>I have the following structure</p>
  <pre><code>&lt;button&gt;
    &lt;OtherComponent /&gt;
  &lt;/button&gt;
  </code></pre>
  <p>OtherComponent just gives a &lt; span /&gt; with an icon, with its own styles.
  I want to pass a style to <strong>button</strong> to override OtherComponent's styles, eg. set the margin to 0. I've tried (doesn't work)</p>
  <pre><code>&lt;button style={{ 'span': { margin: 0 }}}&gt;
    &lt;OtherComponent /&gt;
  &lt;/button&gt;
  </code></pre>