Accessibility

1. Keyboard operation

Every link, button, form control and disclosure on the site is a native HTML element and can be reached and operated with the keyboard alone. A "Skip to main content" link is the first focusable element on each page. FAQ answers and the mobile menu use native details/summary, which open with Enter or Space. Scrollable table wrappers are focusable so their contents can be scrolled with arrow keys. The storage notice at the foot of the page is a non-modal region with two native buttons; it does not trap focus and can also be closed with the Escape key while focus is inside it.

2. Focus visibility

Focused elements show a 3px solid outline in the secondary accent colour with a 2px offset, applied through :focus-visible so that it appears for keyboard users without following mouse clicks. The outline is never removed.

3. Structure, tables and labels

Pages use landmark elements (header, nav, main, aside, footer), one H1 per page and a logical heading order. Frequency tables have a caption, column headers with scope="col" and row headers with scope="row". Every form control has a visible label; hints are linked with aria-describedby; validation errors are listed in text in an alert region and do not rely on colour. Result counts and status messages use polite live regions. Number pools are distinguished by wording, not only by colour.

4. Text, contrast and motion

Body text is 18px on desktop and 16px on small screens with a line height of 1.6; tables use 15px with comfortable row height. Prose is limited to about 68 characters per line. Text sits on translucent panels that resolve to a near-white background over the page gradient, and text colours were chosen to meet a 4.5:1 contrast ratio against that background. The only motion is a 150ms opacity or underline transition and a very slow drift of the blurred background shapes; both are disabled when the operating system requests reduced motion. There is no autoplay, ticker, countdown or scroll hijacking.

5. Without JavaScript

All records, tables, guides and legal text are in the HTML and readable without scripts. Filtering, the on-page CSV download, the correction draft tool and the storage notice require JavaScript; a static CSV file and a text template are provided as fallbacks, and without scripts no storage is written at all.

6. Known limitations

• The main-number frequency table has 50 rows and is long to traverse cell by cell; a summary sentence above the table gives the totals.
• The main-number filter is a select with 50 options. Typing a number while the select is focused moves to it, but the list is long.
• The pages have not been tested with every screen-reader and browser combination; see the handover for tests performed.

7. Reporting a problem

You can describe an accessibility problem with the local draft tool, choosing the topic "Accessibility problem". The tool prepares text on your device; it is not a sent support ticket, and no message endpoint exists in this build.