navbar.css

:root {
    --bg0: #1A1A1D;
    --bg1: #111108;
    --fg0: #EFEFD4;
    --hl-bg: #00AAA0;
  }

  body {
    margin: 0;
    font-family: Arial, Helvetica, sans-serif;
    background-color: var(--bg0);
    color: var(--fg0);
  }

  h1 {
    font-size: 3em;
  }

  h3 {
    font-size: 2em;
  }

  p {
    font-size: 1.5em;
  }

  .body {
    margin: 2cm;
    padding-bottom: 2cm;
  }

  .topnav {
    display: inline-block;
    overflow: hidden;
    background-color: var(--bg1);
  }

  .topnav a {
    float: left;
    color: var(--fg0);
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
    font-size: 17px;
  }

  .topnav a:hover {
    background-color: var(--bg0);
  }

  .topnav a.active {
    background-color: var(--hl-bg);
    color: var(--bg0);
  }

  .link {
    color: var(--hl-bg);
  }

  .link:hover {
      color: var(--bg0);
      background-color: var(--hl-bg);
  }

  div.center {
    text-align: center;
  }

  div.left {
    text-align: left;
    padding-top: 3cm;
    padding-left: 3cm;
  }

  button {
    display: inline-block;
    background-color: #00aaaa;
    border-radius: 10px;
    border: 4px double #000000;
    color: #eeeeee;
    text-align: center;
    font-size: 15px;
    padding: 10px;
    width: 100px;
    -webkit-transition: all 0.5s;
    -moz-transition: all 0.5s;
    -o-transition: all 0.5s;
    transition: all 0.5s;
    cursor: pointer;
    margin: 5px;
    text-align: center;
  }

  .grid-container {
    display: grid;
    grid-template-columns: auto auto auto;
    background-color: var(--bg0);
    padding: 10px;
  }
  .grid-item {
    background-color: var(--bg0);
    border: var(--bg0);
    padding: 20px;
    font-size: 1.5em;
    text-align: center;
  }