A nice old (2016) video of a talk by Heydon Pickering about writing less code. It’s smart, funny, and I agree.
html
Fake centered fixed width
What: Say the background of your website is white and you want, for example, a different color header, full width, with content inside the header that’s contained at a lesser width, and centered. Common enough scenario and usually created with one HTML-element (div, section, …) at full width and with a colored background and one HTML-element (div, article, …) with a fixed width and centered, holding the content.
Make an Accordion with HTML
What: Make a functional accordion with HTML. CSS is optional for styling and no JavaScript is needed. I love simple, I love lightweight, less is more. And in browsers in which it doesn’t work, all the content is still visible, which also improves accessibility.