<!DOCTYPE html>
<title>Two levels of writing mode roots with text inside, no constraints</title>
<link rel="author" title="Morten Stenshorne" href="mstensho@chromium.org">
<link rel="help" href="https://www.w3.org/TR/css-sizing-3/#intrinsic" title="4. Intrinsic Size Determination">
<link rel="help" href="https://www.w3.org/TR/css-writing-modes-3/#orthogonal-auto" title="7.3.1. Available Space in Orthogonal Flows">
<p>There should be three lines below. The middle line should have a
  yellow background (but otherwise be exactly like the two others,
  i.e. no extra height or anything like that)</p>
A B C D E F G
<div style="width:fit-content; background:yellow;">
  A B C D E F G
</div>
A B C D E F G