.invisible {
    left: -999px;
    overflow: hidden;
    position: absolute;
    top: -999px;
  }
  
  .align {
    display: flex;
    justify-content: center;
    flex-direction: column;
    place-items: center;
  }
  
  :root {
    --body-background-color: #82a8ee;
    --body-color: #97adc6;
  }
  
  body {
    background-color: var(--body-background-color);
    display: flex;
    flex-direction: column;
    align-items: center;
    color: var(--body-color);
    margin: 0;
    min-block-size: 100vh;
  }
  a {
    color: inherit;
    outline: 0;
  }
  
  .icons {
    display: none;
  }
  
  .icon {
    block-size: 1em;
    display: inline-block;
    fill: currentcolor;
    inline-size: 1em;
    vertical-align: middle;
  }
  
  .icon--2x {
    font-size: 2rem;
  }

  :root {
    --navigation-background-color: #f0f6ff;
    --navigation-border-radius: 0.25em;
  
    --navigation-anchor-padding: 1.5em;
  }
  
  .navigation {
    background-color: var(--navigation-background-color);
    border-radius: var(--navigation-border-radius);
    box-shadow: 0 0.5em 1em rgba(0, 0, 0, 0.3);
    margin-bottom: 25px;
  }
  
  .navigation ul {
    list-style: none;
    margin: 0;
    padding: 0;
  }
  
  .navigation a {
    display: block;
    padding: var(--navigation-anchor-padding);
    position: relative;
    text-decoration: none;
  }
  
  .navigation a:focus::after,
  .navigation a:hover::after {
    opacity: 1;
  }
  
  .navigation a::after {
    block-size: 100%;
    box-shadow: 0 0.5em 1em rgba(0, 0, 0, 0.3);
    content: '';
    inline-size: 100%;
    left: 0;
    opacity: 0;
    position: absolute;
    top: 0;
    transition: opacity 0.3s;
  }
  
  .navigation--inline ul {
    display: flex;
  }