title: CSS pseudo elements in React
body: <p>I'm building <a href="https://reactjs.org/" rel="noreferrer">React</a> components. I have added CSS inline in the components as suggested in <a href="https://speakerdeck.com/vjeux/react-css-in-js-react-france-meetup" rel="noreferrer">this brilliant presentation</a> by one of the people behind React. I've been trying all night to find a way to add CSS pseudo classes inline, like on the slide titled &quot;::after&quot; in the presentation. Unfortunately, I do not just need to add the <code>content:&quot;&quot;;</code> property, but also <code>position:absolute; -webkit-filter: blur(10px) saturate(2);</code>. The slides show how to add content through <code>{/* … */}</code>, but how would you add other properties?</p>