Popover

Rich content in a floating panel, triggered by a button. Uses the native Popover API.

Component Skill — components/popover/component-skill.md

Native basis

popover attribute — native Popover API with CSS anchor positioning for placement.

Web Platform APIs

popover attribute popovertarget position-area position-try-fallbacks @starting-style

Classes

.popover .popover-header .popover-title .popover-description .popover-content

Attributes

Default

Click the trigger to open a popover below (default side). Uses native Popover API — no JS for open/close.

<button class="btn" data-variant="outline" popovertarget="my-popover">Open Popover</button>

<div class="popover" id="my-popover" popover>
  <div class="popover-header">
    <p class="popover-title">Dimensions</p>
    <p class="popover-description">Set the dimensions for the layer.</p>
  </div>
  <div class="popover-content">...</div>
</div>

With Form

Popover containing form fields — the canonical shadcn popover pattern.

Align

Use data-align on the popover to control horizontal alignment: start, center (default), or end.

Side

Use data-side to position the popover on a specific side of the trigger: top, right, bottom (default), or left.

CSS view file

Uses position-area for anchor positioning, @starting-style for enter animations, and position-try-fallbacks for automatic viewport-overflow flipping. Supports data-side and data-align attributes.

@layer components {
  .popover {
    position: fixed;
    inset: auto;
    margin: 0;
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
    background-color: var(--popover);
    color: var(--popover-foreground);
    padding: 1rem;
    box-shadow: var(--shadow-md);
    width: 20rem;
    opacity: 0;
    translate: 0 -4px;
    transition: opacity 150ms ease, translate 150ms ease, display 150ms allow-discrete;

    /* -- Default: bottom center -- */
    position-area: bottom;
    margin-top: 4px;
    position-try-fallbacks: flip-block;

    &:popover-open {
      opacity: 1;
      translate: 0 0;
    }

    /* ----- Side variants ----- */
    &[data-side="top"] {
      position-area: top;
      margin-top: 0;
      margin-bottom: 4px;
      translate: 0 4px;
      &:popover-open { translate: 0 0; }
    }

    &[data-side="left"] {
      position-area: left;
      margin-top: 0;
      margin-right: 4px;
      translate: 4px 0;
      position-try-fallbacks: flip-inline;
      &:popover-open { translate: 0 0; }
    }

    &[data-side="right"] {
      position-area: right;
      margin-top: 0;
      margin-left: 4px;
      translate: -4px 0;
      position-try-fallbacks: flip-inline;
      &:popover-open { translate: 0 0; }
    }

    /* ----- Align variants (combined with side) ----- */
    &[data-align="start"] {
      &:not([data-side="left"]):not([data-side="right"]) { position-area: bottom left; }
      &[data-side="top"] { position-area: top left; }
      &[data-side="left"] { position-area: left top; }
      &[data-side="right"] { position-area: right top; }
    }

    &[data-align="end"] {
      &:not([data-side="left"]):not([data-side="right"]) { position-area: bottom right; }
      &[data-side="top"] { position-area: top right; }
      &[data-side="left"] { position-area: left bottom; }
      &[data-side="right"] { position-area: right bottom; }
    }
  }

  @starting-style {
    .popover:popover-open { opacity: 0; translate: 0 -4px; }
    .popover[data-side="top"]:popover-open { opacity: 0; translate: 0 4px; }
    .popover[data-side="left"]:popover-open { opacity: 0; translate: 4px 0; }
    .popover[data-side="right"]:popover-open { opacity: 0; translate: -4px 0; }
  }

  .popover-header { margin-bottom: 0.75rem; }
  .popover-title { margin: 0; font-size: 0.875rem; font-weight: 500; color: var(--foreground); }
  .popover-description { margin: 0.25rem 0 0; font-size: 0.8125rem; color: var(--muted-foreground); }
  .popover-content { font-size: 0.875rem; }

  @media (prefers-reduced-motion: reduce) {
    .popover {
      transition: none;
    }
  }
}

JavaScript view file

Assigns unique CSS anchor names per trigger–popover pair. Opening, closing, and light-dismiss are handled entirely by the native popovertarget attribute.

// -- Popover --------------------------------------------------
// CSS anchor positioning for popover components.

function init() {
  document.querySelectorAll('[popovertarget]:not([data-init])').forEach((trigger) => {
  trigger.dataset.init = '';
  const id = trigger.getAttribute('popovertarget');
  const popover = document.getElementById(id);
  if (!popover || !popover.classList.contains('popover')) return;

  // CSS anchor positioning - unique name per trigger-popover pair
  const anchorId = `--popover-${id}`;
  trigger.style.anchorName = anchorId;
  popover.style.positionAnchor = anchorId;
});
}

init();
new MutationObserver(init).observe(document, { childList: true, subtree: true });