basicHTML_CSS-Padding.html

<!DOCTYPE html>
<html lang="en" dir="ltr">
  <head>
    <meta charset="utf-8">
    <title> My trial page </title>
    <style>
    .injected-text {
      margin-bottom: -25px;
      text-align: center;
    }

    .box {
      border-style: solid;
      border-color: black;
      border-width: 5px;
      text-align: center;
    }

    .yellow-box {
      background-color: yellow;
      padding: 10px;
    }

    .red-box {
      background-color: crimson;
      color: #fff;
      padding: 20px;
    }

    .blue-box {
      background-color: blue;
      color: #fff;
      padding: 10px;
    }
    </style>
</head>
  <body>
    <h5 class="injected-text">padding</h5>

    <div class="box yellow-box">
      <h5 class="box red-box">padding</h5>
      <h5 class="box blue-box">padding</h5>
    </div>
  </body>
</html>