Accessibility

• ContrastBody and label colours were measured against the buff ground rather than assumed. Fourteen places were failing at around 2.3:1 and were raised; nothing carrying information now recedes by being too faint to read.
• Target sizeEvery control meets the 24px minimum, and the ones used one-handed outdoors are 44px. The panel toggle spans the full width of the sheet.
• KeyboardEverything is reachable and operable by keyboard. The focus ring is a two-pixel outline defined outside the utility layer so a stray class cannot remove it. Disclosures use native details and summary, so they behave the way the browser already knows how to.
• Motionprefers-reduced-motion removes every animation, and the interface is complete with every pixel held still. The marching route line stops; the route stays drawn.
• Colour aloneNo verdict is carried by colour alone. Every hue is paired with a word, and restricted areas are hatched as well as tinted, which also keeps them legible without colour vision.
• Zoom and small screensVerified with no horizontal scrolling at 320, 375, 414 and 768 pixels.

• The map itselfThe chart is a WebGL canvas and is not readable by a screen reader. Every answer it produces is also written out in the panel beside it as text, and the site is fully usable by searching an address instead of clicking, but the map is a picture and cannot be navigated by keyboard.
• Small labelsField labels are set at 10px uppercase, which is small. It is a deliberate convention borrowed from chart marginalia and it passes contrast, but it is at the edge of comfortable and browser zoom is the only remedy today.
• No formal auditThe conformance claim is from our own testing. No independent audit has been carried out, so treat AA as the target rather than a certified result.

If something here is unusable for you, that is a defect and worth reporting. Describe the page, what you were trying to do, and the assistive technology and browser you were using.