Accessibility
Built to be read by everyone
Accessibility is part of how this site is built, not a feature bolted on later. Here is what that means in practice, and how to tell us if something gets in your way.
Works with a keyboard
Every link, button, and menu can be reached and used with the keyboard alone, with a visible focus outline so you always know where you are.
Works with a screen reader
Pages use real headings, landmarks, and labels. Each page has one main heading, a skip-to-content link, and a labeled navigation region.
Readable contrast
Text colors are chosen to meet AA contrast on the background behind them, so the words stay legible without straining.
Reflows and zooms
The layout reflows on a small screen and holds up at 400% zoom, so you can make the text larger without losing content off the side.
No script needed to read
Lessons are plain server-rendered pages. You do not need to run any script to read them, and the site stores nothing on your device.
Respects reduced motion
If your device asks for reduced motion, animations and transitions are turned off.
Our aim
The standard we work toward
We aim to meet the Web Content Accessibility Guidelines (WCAG) 2.2 at level AA. That is the target we hold ourselves to; we are always fixing what falls short of it.
If something on this site is hard to use with your assistive technology, tell us and we will fix it. Email [email protected] with the page and what got in your way.