<!DOCTYPE html>
<html>
  <meta charset="utf-8">
  <title>CSS Test Reference</title>
  <style>
  .line {
    display: flex;
  }

  .container {
    writing-mode: horizontal-tb;
    direction: ltr;

    block-size: 200px;
    inline-size: 200px;
    margin: 10px;
    background: deepskyblue;
  }

  .content {
    inline-size: 100%;
    block-size: 200%;
    background: lightsalmon;
  }
  </style>

  <div class="line">
    <div id="auto-auto" class="container" style="overflow-y: auto; scrollbar-gutter: stable both-edges">
      <div class="content"></div>
    </div>

    <div id="scroll-auto" class="container" style="overflow-y: scroll; scrollbar-gutter: stable both-edges">
      <div class="content"></div>
    </div>

    <div id="hidden-auto" class="container" style="overflow-y: hidden; scrollbar-gutter: stable both-edges">
      <div class="content"></div>
    </div>
  </div>

  <div class="line">
    <div id="auto-stable" class="container" style="overflow-y: auto; scrollbar-gutter: auto">
      <div class="content"></div>
    </div>

    <div id="scroll-stable" class="container" style="overflow-y: scroll; scrollbar-gutter: auto">
      <div class="content"></div>
    </div>

    <div id="hidden-stable" class="container" style="overflow-y: hidden; scrollbar-gutter: auto">
      <div class="content"></div>
    </div>
  </div>

  <div class="line">
    <div id="hidden-stable-both" class="container" style="overflow-y: auto; scrollbar-gutter: stable">
      <div class="content"></div>
    </div>

    <div id="hidden-stable-both" class="container" style="overflow-y: scroll; scrollbar-gutter: stable">
      <div class="content"></div>
    </div>

    <div id="hidden-stable-both" class="container" style="overflow-y: hidden; scrollbar-gutter: stable">
      <div class="content"></div>
    </div>
  </div>
</html>
