Accessibility

• Native controls throughout. Every input is a real <input>, <select> or <textarea> with an associated label. No custom widget re-implements behaviour the browser already provides correctly.
• Full keyboard operation. Every calculator can be completed without a mouse. Search supports arrow-key navigation and Enter to select; / focuses it from anywhere; Escape closes overlays and returns focus.
• Visible focus. A two-pixel outline with offset on every interactive element, never removed.
• Errors are announced. Validation messages use role="alert", are linked to their field with aria-describedby, and describe what to do rather than just that something is wrong.
• Results are announced. Search result counts are exposed through a polite live region so screen reader users learn how many matches there are without hunting.
• Semantic structure. One h1 per page, a logical heading hierarchy, landmarks for header, navigation, main and footer, and a skip link as the first focusable element.
• Tables are real tables with scope-marked headers, and they scroll inside their own container so the page never scrolls sideways.
• Charts are supplementary. Every figure a chart shows is also stated in the metrics and tables, and each chart carries a text description of the trend. No information exists only in a graphic.
• Zoom and reflow. Pinch-zoom is never disabled, and layouts reflow to a single column without horizontal scrolling down to a 320-pixel viewport.
• Reduced motion. All transitions and smooth scrolling are disabled when the operating system requests reduced motion.
• Colour is never the only signal. Breakdown segments carry labels and values, not just colours, and the palette is chosen to remain distinguishable with common colour vision deficiencies.

Structure, labelling, keyboard operation and contrast have been designed to WCAG 2.2 AA and checked during development. Body text meets or exceeds a 4.5:1 contrast ratio in both light and dark themes; large text and interface components meet 3:1.

This site has not had a formal third-party accessibility audit, and it has not been tested across the full range of assistive technologies. We are not claiming certified conformance — we are describing what has been built and checked. Real-world testing with screen readers other than the ones used during development is the most valuable thing still outstanding.

If something here does not work with your assistive technology, that is a defect and we want to fix it. Please get in touch with the page, what you were trying to do, and the technology you were using. Reports like these are more useful than any automated checker.