I completely agree with the maker's point that class names are the bane of CSS design. However, styled components have been amazing in this regard. I've tried a lot of solutions over the past 8 years and this is my favorite by far. No extra crap, but you still get reusability and the syntax is like plain CSS. I tried JSS but I can't get over defining styles as JS objects, not to mention made Typescript slow to a crawl.

React example:

``` import styled from 'styled-components';

const Button = styled.button` padding: 4px; font-weight: bold; `;

const PrimaryButton = styled(button)` background: ${primaryColor}; color: white; `;

```