via @codylindley “A visual way to understand CSS specificity.”
CSS
CSS Values
A handy, search-driven CSS reference for properties and values
Cicadients
“A reworking of the first two examples of “The Cicada Principle and Why It Matters to Web Designers” using CSS gradients. “
Stylesheet Download Tests
This page tests “whether today’s browsers will download stylesheets that are referenced with media queries that would not apply on that browser or device.”
Thee appears to be a lot of download overhead with media queries using link elements.
The Shapes of CSS
The Web Platform: Browser technologies
Critical bookmark for Web devs, as it’s an excellent index of browser technologies (HTML5, JavaScript, CSS, storage etc.).