*, *::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;
  }

@media (min-width: 40em) {

  header {
    justify-content: space-between;
    display: flex;
    align-items: center;


    ul {
      display: flex;

    }

    a {
      border-top: 0;
    }
  }

  .cards {
    display: flex;
    flex-wrap: wrap;
    gap: 1em;

    li {
      flex-basis: 30%;
    }
  }

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

  .sidebar {
    width: 150%;
    margin: 1rem;
    margin-inline: 0;

  }


  body {
    max-width: 80rem;
    margin: 0 auto;
  }
}