The article is about css，there are five things you need to know.

1. you don't need a naming convention.
   because all selectors exist in the same global namespace, over time it becomes very likely that you'll run into unexpected side effects such as selectors targeting elements that you didn't intend, or selectors being overridden by other selectors. So, we have side-stepped these issues with methodologies(OOCSS, SMACSS, or more popular BEM) that define naming conventions to help us avoid class name collisions;

2. you don't need float
   flexbox is a wonderful module layout

3. you don't need a grid framework
   you can use css grid layout

4. you don't need a preprocessor
   Modern browsers now have native support for CSS variable ** and ** calc(). Other feature such as color modifications, and mixins are not far behind.
   PortCSS is a "tool for transforming CSS with Javascript"，Use tomorrom's CSS, today
   Babel：Use next generation Javascript， today.

5. you don't need css
   you can style web applications without ever writing a single .css file.
   you can use jss and styled-components