After eight years of designing in the browser, this is a short list of things I believe to be true.
What good CSS does
- Doesn't break any functionality of plain html.
- Makes an interface more readable for everyone on any device.
- Enhances the usability of an interface for all devices.
- Allows you to quickly change a single interface without breaking other unseen interfaces.
- Renders quickly in the browser.
- Is 60fps (no jank on window resize or during scrolling).
What good CSS is
- Highly reusable - even across projects.
- Well documented.
- Easy to read and understand.
- ID free.
- Easy to maintain.
- Very very small.