| <!DOCTYPE html> |
| <title>CSS Anchor Positioning Test: popover with anchor functions transition ::backdrop</title> |
| <link rel="help" href="https://drafts.csswg.org/css-anchor-position-1/"> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <div id="anchor"></div> |
| <div id="popover" popover></div> |
| <style> |
| #anchor { |
| anchor-name: --anchor; |
| } |
| #popover { |
| top: anchor(--anchor bottom); |
| } |
| ::backdrop { |
| transition: opacity 1s step-end; |
| opacity: 1; |
| } |
| @starting-style { |
| ::backdrop { |
| opacity: 0; |
| } |
| } |
| </style> |
| <script> |
| test(() => { |
| popover.showPopover(); |
| assert_equals(getComputedStyle(popover, "::backdrop").opacity, "0"); |
| }, "Anchored popover ::backdrop transitioning opacity with @starting-style"); |
| </script> |
