Accessibility

The target

We build to the Web Content Accessibility Guidelines 2.2 at level AA. Automated checks run on the main pages every time the site is built. Automated checks find only some problems, so we also test by hand with a keyboard and a screen reader.

What the site does

• Every page works with a keyboard alone, with a visible focus outline.
• Colour is never the only signal. Evidence levels, source standing and fit levels each carry a word and a shape as well as a colour.
• Text and controls meet AA contrast in the light and the dark theme. The theme follows your system setting unless you choose one.
• Text scales with your browser setting and pages reflow on small screens without sideways scrolling.
• Pages work without JavaScript, apart from the tools that need it. The troubleshooting trees, for example, read as a full outline when scripts are off.
• Animations stop when you ask your system for reduced motion, and the menu has its own switch.
• Every drawing has a text alternative. Interactive models have a plain description and a still version.

Known gaps

• Some older seller pages that we cite are not accessible. We cannot change them.
• Scientific drawings show fine detail that a text alternative can only summarise.

Report a problem

If a page does not work for you, tell us which page, what you were using, and what went wrong. We treat accessibility reports as bugs and fix them first.