title: Overflow hidden does not fully hide parent div with border radius
body: <p>I am getting some residual overflow from my simple layout below. Though minimal, the effect is quite obvious and happens only where I set a border radius. The expected behavior is to have the <code>div class='inner'</code>, the white, fully cover <code>div class='outer'</code>, the red. However there clearly seems to be residual overflows from both ends of the div.</p>
  <p><strong>Example:</strong></p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>.outer {
    background-color: red;
    width: 500px;
    height: 50px;
    position: relative;
    overflow: hidden;
    border-radius: 5rem;
  }
  .inner {
    background: white;
    width: 100%;
    height: 100%;
    position: absolute;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="outer"&gt;
    &lt;div class="inner"&gt;&lt;/div&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  <p>I am using this as part of a loading bar effect where <code>inner</code> translates as part of an animation during a media play. I have read a couple other problems that involve adding properties like <code>z-index</code> and adding <code>masks</code> but does not work for me. Also read issues with <code>webkit</code>, but have not found anything that works in the case above.</p>
  <p><strong>Edit</strong></p>
  <p>For clearer illustration refer below:-
  Overflow hidden is being used so that when inner translates, any overflow is hidden out of the parent div. I am unsure if there are any other ways I can use. Below is an example of having the x-axis translate at 10%. I am trying to achieve the overflow effect without any bleeding from the edges around where border radius is applied.</p>
  <p>Translate starts at 0% which is the same as the example above.</p>
  <p>This issue was also reported - <a href="https://bugs.chromium.org/p/chromium/issues/detail?id=491574" rel="nofollow noreferrer">Issue 491574: border-radius bleeds background-color</a></p>
  <p>And similar to the question - <a href="https://stackoverflow.com/questions/41174981/css-border-radius-background-colour-bleed">CSS border radius background colour bleed</a> but the use case of overflow does not apply to my case.</p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>.outer {
    background-color: red;
    width: 500px;
    height: 50px;
    position: relative;
    border-radius: 5rem;
    overflow: hidden;
  }
  .inner {
    background: white;
    width: 100%;
    height: 100%;
    position: absolute;
    transform: translateX(10%);
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="outer"&gt;
    &lt;div class="inner"&gt;&lt;/div&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  <p>The code above though not in exact flavor is embedded in an app written in ReactJS and I am facing this issue both in Chrome and Mozilla.</p>