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<style>.demo { button:focus-visible { outline:3px solid currentColor; outline-offset:3px; }; }</style><main class="demo">Example content</main>
Engineering judgment: Use :focus-visible when the design needs a keyboard-focused ring without forcing the same treatment for every pointer interaction.
A good CSS change narrows the problem. Use :focus-visible when the design needs a keyboard-focused ring without forcing the same treatment for every pointer interaction. This keeps the rule understandable when content, theme, or viewport conditions change later.
<style>.demo { input:checked + label { font-weight:700; }; }</style><main class="demo">Example content</main>
In production, Do not remove focus because a custom hover style looks cleaner. Focus visibility is a core interaction signal, especially for keyboard users. That is the kind of bug that survives visual spot checks because the stylesheet is syntactically valid while the layout contract is wrong.
| Concern | What to inspect | Typical failure |
|---|---|---|
| Core behavior | Pseudo-Classes for Interactive States | Do not remove focus because a custom hover style looks cleaner. Focus visibility is a core interaction signal, especially for keyboard users. |
| Production test | Real content and constraints | The rule works only for the demo values |
| Maintenance | Scope and override path | A later fix creates another exception |
The useful mental model here is practical: how pseudo-classes expose state such as hover, focus, checked, disabled, and user interaction preferences. When a rule looks obvious but the browser produces something else, start by identifying which constraint or rendering phase is actually winning.
<style>.demo { button:disabled { cursor:not-allowed; opacity:.55; }; }</style><main class="demo">Example content</main>
Disabled state is useful here because it demonstrates pseudo-classes for interactive states under a concrete input rather than as an abstract property list.
<style>.demo { input:invalid { border-color:crimson; }; }</style><main class="demo">Example content</main>
Valid state is useful here because it demonstrates pseudo-classes for interactive states under a concrete input rather than as an abstract property list.
Finish the lesson once you have worked through the material. This awards ★ 30 XP.