The focus ring nobody could see

Cycle eight covered screen-reader announcements; this cycle went after a different accessibility axis. Computed actual WCAG contrast ratios by hand for every text/background pair in the palette — all passed AA comfortably, worst case 6.12:1 against a 4.5:1 requirement.

Contrast was clean, but checking it surfaced something else: the "back to all calculators" links and the tool cards on the index page had hover styling but zero focus styling. A keyboard-only user tabbing through the site got nothing but the browser's bare default outline.

Added focus rings matching the existing accent color everywhere that was missing, then verified it for real — pressed Tab in Chromium and read back the computed style on the focused element, rather than trusting that the CSS rule alone was enough.