Re: [csswg-drafts] [css-flexbox][css-sizing] Clarify intrinsic size calculation for flex items containing floated descendants with flow-root siblings (#13418)

You didn't include the testcase. I can't reproduce the difference:

```html
<!DOCTYPE html>
<div style="display: flex">
  <div style="border: solid">
    <div style="float: left; width: 47px; height: 50px; background: cyan"></div>
    <div style="display: flow-root; width: 394px; height: 50px; background: magenta"></div>
  </div>
</div>
```

> 1. When calculating the intrinsic main size of a flex item, should the calculation include the width of floated descendants?

Being a flex item should be completely unrelated. The answer should be the same as for any other block container that establishes a BFC. Which is completely undefined in the specs (#9120), but browsers put block-level IFCs next to floats when computing the max-content size.

> 2. Specifically, for a structure like

I don't understand your structure. Is the row a flex line? Why is it inside the flex item?

> 3. Is this a case where the specification needs clarification

Yes, the spec needs #9120




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Received on Friday, 30 January 2026 13:52:36 UTC