<style>
  * {
    box-sizing: border-box;
  }

  body {
     margin: 0;
     max-width: 1200px;
     margin-left: auto;
     margin-right: auto;
  }

  header {
     background-color: lightblue;
     text-align: center;
     padding: 2px;
     font-size: 25px;
     color: white;
  }

  section {
     display: flex
  }

  nav {
     width: 30%;
     background: #fff;
     padding: 20px;
  }

  nav ul {
     list-style-type: none;
     padding: 0;
  }

  article {
     padding: 20px;
     width: 70%;
     background-color: #f1f1f1;
  }

  footer {
     background-color: lightblue;
     padding: 10px;
     text-align: center;
     color: white;
  }

</style>
