title: Using FAST Is there a way to apply styles to child ShadowDOM elements?
body: <p>I've been working with the FAST toolkit (<a href="https://fast.design" rel="nofollow noreferrer">https://fast.design</a>) creating my own elements that I wish to use. Part of that journey has lead me to make a <code>Toolbar</code>.</p>
  <p>Been a <code>Toolbar</code>, I want to change the background of the buttons to be transparent (going for a look like: <a href="https://fluentsite.z22.web.core.windows.net/components/toolbar/definition" rel="nofollow noreferrer">https://fluentsite.z22.web.core.windows.net/components/toolbar/definition</a>. Now I could create another element, i.e. <code>ToolbarButton</code> that extends <code>Button</code> (and any other controls which need the background removed) and it'll work for my purpose. Still, it feels like something I should be able to do as it's a unique trait of the <code>Toolbar</code>.</p>
  <p>I'm not sure if it's even possible, but I can't figure it out looking through the documentation and source code on GitHub.</p>
  <p>Any advice would be appreciated.</p>
  <p>Ref: <a href="https://github.com/microsoft/fast/issues/3548" rel="nofollow noreferrer">https://github.com/microsoft/fast/issues/3548</a></p>