title: child div with border radius shows color of parent div at borders
body: <p>I have 2 divs, one is parent and 2nd is child div as follows</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: #211182;
      height: 50px;
  }
  
  .inner{
      height: 50px;
      border-radius: 60px 0 0 0;
      background: #f9f9f9
  }</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>only child div has border-radius.
  it shows parent background color at border of child div which is not expected.
  I tried <code>overflow: hidden</code> , also tried <code>border : none</code> and <code>border-width : 0</code> and <code>width : 100%; height:100%</code> but no luck.
  please help me to resolve this.
  Attaching screenshot of the result.
  <a href="https://i.stack.imgur.com/Y00bU.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Y00bU.png" alt="enter image description here" /></a></p>