Halfmoon is a front-end framework with a built-in dark mode and full customizability using CSS variables; great for building dashboards and tools.

Here's what I'd like you to know upfront: this is a hard problem. If you've landed here because you're hoping to be pointed at a tool you can run that tells you exactly what CSS you can delete from your project, well... there are tools out there, but I'm warning you to be very careful with them because none of them can ever tell you the complete story. Post written by Chris Coyer.

Sal (Scroll Animation Library) is written with aim to provide performant and lightweight solution for animating elements on scroll. It's based on the Intersection Observer, which gives amazing performance in terms of checking the element's presence in viewport.