body {
    font-family: Arial, Helvetica, sans-serif;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px;
    border: solid 2px #0055FF;
    font-size: 1.25em;
    height: 1.5em;
  }
  
  a {
    text-decoration: none;
  }

  h1 {
      color: darkblue
  }
  
  main {
    border: solid 2px #00FF55;
    padding: 10px;
    margin-top: 10px;
  }
  
  article {
    border-bottom: solid 2px #00FF55;
  }

  button {
    font-size: 18px; 
    padding: 5px; 
    width: 5em;
    margin-bottom: -10px;
  }