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<link rel="author" title="David Grogan" href="dgrogan@chromium.org">
<link rel="help" href="https://html.spec.whatwg.org/multipage/rendering.html#the-details-and-summary-elements">
<link rel="match" href="details-display-property-is-ignored-ref.html">
<link rel="bookmark" href="https://bugs.chromium.org/p/chromium/issues/detail?id=635282" />
<meta name="assert" content="The display property is ignored on details elements and is instead always rendered as a block box." />

From <a href="https://html.spec.whatwg.org/multipage/rendering.html#the-details-and-summary-elements">html.spec.whatwg.org</a>:

<blockquote>
The details element is expected to render as a block box. The element's shadow
tree is expected to take the element's first summary element child, if any, and
place it in a first block box container, and then take the element's remaining
descendants, if any, and place them in a second block box container.
</blockquote>

&lt;details display:flex> should be ignored. Otherwise details would render as
something other than a block box.
<hr>

<details open style="display:flex;">
  <summary>This is the summary.</summary>
  <div>thing 1</div>
  thing 2
</details>
