The WordPress developers blog has a very good how-to article on customizing embeds.

This is a meta thought piece about Responsive Web Design and what has come after.

Kevin Powell has a useful short about the :empty element and how you can use it to solve a common problem.

Kevin Powell and Bramus show how Multi Page Animated view transitions work.

Kevin Powell, a CSS expert and effective teacher, has released a free course on HTML and CSS. These are two of the fundamental languages behind all websites, not to mention all page builders and Gutenberg.

A number of people like to create their own CSS framework. They start with the basics, as this video from Paul Charlton shows how to do, and over time they build it up with just the features they need.

A short from Kevin Powell on an easy way to improve your forms.

Here is a quick video showing the Advanced Themer Recipes and CSS Superpower features.

This may be of interest to some. Results of the Front End tech survey. TypeScript is well established now. I was surprised at the percentage of MacOS users.