Every Sass tutorial on the internet will teach you to use mixin for media queries. Why though? All it does is adding unnecessary abstraction.
CSS Variable has taken the frontend development by storm. I was skeptical of it because I'm used to Sass variable. But it's more powerful than that.
Learn about the basic of Sticky position and some advanced tips like adding a class when the element becomes sticky.
I often see a site unknowingly load both desktop and mobile images. But that is understandable since the way image loading works is quite weird.
Update 11 Aug 2020: WordPress 5.5 introduced native lazy loading by adding loading="lazy" attribute to all images. So you no longer need to create your own. Lazy-load is a way to prevent…