body {
  background: #000 url('https://www.transparenttextures.com/patterns/stardust.png');
  color: #00ffcc;
  font-family: 'Verdana', sans-serif;
  margin: 0;
  padding: 0;
}

.container {
  width: 800px;
  margin: auto;
  padding: 20px;
  background-color: #111;
  border: 4px double #00ffcc;
  box-shadow: 0 0 20px #00ffcc;
}

header {
  text-align: center;
  background-color: #222;
  padding: 20px;
  border-bottom: 2px dashed #00ffcc;
}

header h1 {
  font-family: 'Comic Sans MS', cursive;
  font-size: 3em;
  margin: 0;
  color: #ff66ff;
}

nav ul {
  list-style: none;
  display: flex;
  justify-content: space-around;
  padding: 0;
  margin: 0;
  background-color: #222;
  border-top: 2px solid #00ffcc;
  border-bottom: 2px solid #00ffcc;
}

nav ul li a {
  color: #00ffcc;
  text-decoration: none;
  padding: 10px 20px;
  display: block;
}

nav ul li a:hover {
  background-color: #333;
  color: #ff66ff;
}

.tabcontent {
  display: none;
  padding: 20px;
}

.tabcontent:target {
  display: block;
}

footer {
  text-align: center;
  font-size: 0.8em;
  margin-top: 30px;
  padding-top: 10px;
  border-top: 1px dotted #00ffcc;
}