title: I am not able to fill the round corners with color using css?
body: <p>I have made two <code>div</code> tags in html and the outermost div tag has round corners but when I try to fill the inner <code>div</code> with color but there is some white space left above inner <code>div</code> (see screenshot for more clarification). I want  to fill the colour entirely for <code>class-"header"</code>. I want to fill the white space near upper corners with blue color.</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>#widget {
    position: fixed;
    left: 340px;
    top: 75px;
    width: 450px;
    height: 500px;
    border-style: solid;
    border-width: 1px;
    box-shadow: 0 0 4px 0;
    border-radius: 10px;
  }
  
  .container {
    background-color: #0071B3;
    width: 450px;
    height: 250px;
  }
  
  .header {
    text-align: center;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div id="widget"&gt;
    &lt;div class="container"&gt;
      &lt;div class="header"&gt;
        &lt;h4&gt;Let's Enhance&lt;/h4&gt;
      &lt;/div&gt;
      &lt;div class="info"&gt;
        &lt;div&gt;
        &lt;/div&gt;
      &lt;/div&gt;</code></pre>
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  <p><a href="https://i.stack.imgur.com/6F10s.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/6F10s.png" alt="enter image description here"></a></p>