.ad-slot {
  margin: 2em auto;
  text-align: center;
  border: 1px dashed #0f0;
  padding: 1em;
  background: #222;
  color: #0f0;
  font-size: 0.9em;
}

.ad-slot:before {
  content: "Advertisement";
  display: block;
  margin-bottom: 0.5em;
  color: #aaa;
  font-size: 0.8em;
}

body {
  font-family: "Courier New", Courier, monospace;
  background-color: #111;
  color: #0f0;
  line-height: 1.6;
  margin: 0;
  padding: 0;
}

header {
  background: #222;
  padding: 1em;
  text-align: center;
  border-bottom: 2px solid #0f0;
}

header h1 {
  font-size: 2.5em;
  margin: 0;
  color: #0f0;
}

header p {
  font-size: 1.2em;
  color: #0a0;
}

a {
  color: #0f0;
  text-decoration: none;
}

a:hover {
  color: #fff;
  text-decoration: underline;
}

main {
  padding: 2em;
  max-width: 800px;
  margin: auto;
}

ul {
  list-style-type: none;
  padding: 0;
}

ul li {
  margin: 0.5em 0;
  font-size: 1.2em;
}

ul li a {
  display: block;
  padding: 0.5em;
  border: 1px dashed #0f0;
  background: #222;
  transition: background 0.3s, color 0.3s;
}

ul li a:hover {
  background: #0f0;
  color: #111;
}