*, *::after, *::before {
      box-sizing: border-box;
  }

  :root {
    font:1.2em/1.4 Arial, Helvetica, sans-serif;
  }

  body {
    padding: 0 0 1em;
  }

  header {
    background-color: #333;
    color: #fff;
    border: 5px solid #000;
  }

  header ul {
    list-style: none;
    margin: 0;
    padding: 0;
  }

  header a {
    color: #fff;
    text-decoration: none;
    display: block;
    padding: 0.5em 1em;
    border-top: 1px solid #999;

  }

  header .title {
    font-size: 150%;
    font-style: italic;
    font-weight: bold;
    padding: 1em;
  }

  main {
    padding: 0 1em;
  }

  .cards {
    list-style: none;
    margin: 0;
    padding: 0;
  }

  .cards li {
    border: 5px solid #000;
    margin-bottom: 1em;
  }

  .cards h2 {
    background-color: #333;
    color: #fff;
    margin: 0;
    padding: 0.5em 1em;
  }

  .cards .inner {
    padding: 0.5em 1em;
  }

  .sidebar {
    background-color: #333;
    border: 5px solid #000;
    padding: 0.5em 1em;
    color: #fff;
  }
.container {
    max-width: 80rem;
}
  /*Alle onnodige dinges er uit zetten.*/
  @media (min-width: 40em) {
      *, *::after, *::before {
          box-sizing: border-box;
      }

      :root {
          font:1.2em/1.4 Arial, Helvetica, sans-serif;
      }

      body {
          padding: 0 0 1em;
      }

      header {
          background-color: #333;
          color: #fff;
          border: 5px solid #000;
          justify-content: space-between;
          display: flex;
          align-items: center;
      }

      header ul {
          display: flex;
          list-style: none;
          margin: 0;
          padding: 0;
      }

      header a {
          color: #fff;
          text-decoration: none;
          display: block;
          padding: 0.5em 1em;
          border-top: 0;
      }

      header .title {
          font-size: 150%;
          font-style: italic;
          font-weight: bold;
          padding: 1em;
      }

      main {
          padding: 0 1em;
          display: flex;

      }

      .cards {
          display: flex;
          list-style: none;
          margin: 0;
          padding: 0;
          gap: 1em;
          flex-wrap: wrap;
      }

      .cards li {
          border: 5px solid #000;
          margin-bottom: 1em;
          flex-basis: 30%;
      }

      .cards h2 {
          background-color: #333;
          color: #fff;
          margin: 0;
          padding: 0.5em 1em;
      }

      .cards .inner {
          padding: 0.5em 1em;
      }

      .sidebar {
          width: 150%;
          margin: 1rem;
          margin-inline: 0;
          background-color: #333;
          border: 5px solid #000;
          padding: 0.5em 1em;
          color: #fff;
          text-align: center;
      }

  }