The ring is the same on every control, and written once: --border-emphasis of --accent, standing --focus-offset off the box, plus a halo --focus-halo wide in --accent-ring — 2, 2 and 3 px. A field that already has an accent border keeps the halo alone.

:focus-visible, never :focus — a mouse click should not light the ring. Focus order follows the source. Nothing in this system is reachable by pointer only.