Frontend & browser·Accessibility and semantics
the outline appears when you tab to the button and not when you click it.
:focus-visible
Also calledfocus ring, focus indicator
A pseudo-class matching only when the browser judges a focus indicator should be shown, which in practice means keyboard focus rather than mouse clicks. It resolves the old argument that led designers to remove focus outlines entirely and made keyboard use impossible. Removing the default outline is only acceptable if something with sufficient contrast replaces it.