Baseline 2024

Newly available

Since April 2024, this feature works across the latest devices and browser versions. This feature might not work in older devices or browsers.

The :popover-open CSS pseudo-class represents a popover element (i.e. one with a popover attribute) that is in the showing state. You can use this to apply style to popover elements only when they are shown.


:popover-open {
  /* ... */


By default, popovers appear in the middle of the viewport. The default styling is achieved like this in the UA stylesheet:

[popover] {
  position: fixed;
  inset: 0;
  width: fit-content;
  height: fit-content;
  margin: auto;
  border: solid;
  padding: 0.25em;
  overflow: auto;
  color: CanvasText;
  background-color: Canvas;

To override the default styles and get the popover to appear somewhere else on your viewport, you could need to override the above styles with something like this:

:popover-open {
  width: 200px;
  height: 100px;
  position: absolute;
  inset: unset;
  bottom: 5px;
  right: 5px;
  margin: 0;


HTML Standard
# selector-popover-open

Browser compatibility

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See also