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CSS-Only Popovers & Tooltips

When to Use

Use the Popover API (popover attribute + popovertarget) for click-triggered panels with built-in light dismiss and focus trapping. Use CSS :hover + ::after for simple hover tooltips that need to work everywhere.

Decision

Client asks for... Use... Why
Tooltip on hover popover=hint + anchor positioning (Chrome) or CSS :hover + absolute Native tooltip behavior
Click-triggered popover popover attribute + popovertarget Built-in light dismiss, focus trap
Dropdown menu popover + anchor positioning Positioned relative to trigger
Info popover with arrow popover + anchor() + ::before arrow Positioned and styled
Cross-browser tooltip :hover + ::after pseudo-element Works everywhere

Pattern

<!-- Popover API — all browsers -->
<button popovertarget="info-popup">More info</button>
<div id="info-popup" popover>
  <p>Additional information here.</p>
</div>

[popover] {
  border: 1px solid oklch(85% 0 0);
  border-radius: 8px; padding: 1rem;
  box-shadow: 0 4px 16px oklch(0% 0 0 / 0.12);
  opacity: 0; transform: translateY(8px);
  transition: opacity 0.2s, transform 0.2s,
    display 0.2s allow-discrete, overlay 0.2s allow-discrete;
}
[popover]:popover-open { opacity: 1; transform: translateY(0); }
@starting-style {
  [popover]:popover-open { opacity: 0; transform: translateY(8px); }
}

/* Cross-browser hover tooltip */
.has-tooltip { position: relative; }
.has-tooltip::after {
  content: attr(data-tooltip);
  position: absolute; bottom: calc(100% + 8px); left: 50%;
  transform: translateX(-50%);
  background: oklch(20% 0 0); color: white;
  padding: 0.4rem 0.6rem; border-radius: 4px;
  font-size: 0.8rem; white-space: nowrap;
  opacity: 0; pointer-events: none;
  transition: opacity 0.15s;
}
.has-tooltip:hover::after,
.has-tooltip:focus-visible::after { opacity: 1; }

Common Mistakes

  • Using JS libraries for simple tooltips — CSS :hover + ::after or the Popover API handles most cases
  • Forgetting popovertarget — the button needs popovertarget="id" to toggle the popover
  • Not providing keyboard access — :hover tooltips need :focus-visible equivalent
  • Missing position-try-fallbacks on anchored elements — without it, tooltips overflow viewport edges

See Also