body {
  font-family: Courier, monospace;
  margin: 0;
  padding: 0;
  background: #111;
  color: #eee;
  font-size: 16px;
  transition: all 0.3s;
}
body.light {
  background: linear-gradient(to bottom, #f5f5fa 0%, #e0e0f0 100%);
  color: #222;
}
header {
  background: #000;
  color: #ff0;
  padding: 20px;
  text-align: center;
  font-size: 2em;
  border-bottom: 2px solid #ff0;
  transition: all 0.3s;
}
body.light header {
  background: #1a2a4f;
  color: #fff;
  border-bottom: 2px solid #0066cc;
}
nav {
  background: #333;
  text-align: center;
  padding: 10px;
  transition: all 0.3s;
}
body.light nav {
  background: #1a2a4f;
}
nav a {
  color: #ff0;
  text-decoration: none;
  margin: 10px;
  padding: 8px 15px;
  display: inline-block;
  background: #444;
  border-radius: 5px;
  font-size: 1.1em;
  transition: all 0.3s;
}
body.light nav a {
  background: rgba(0, 102, 204, 0.9);
  color: #fff;
  font-weight: bold;
}
nav a:hover {
  background: #666;
}
body.light nav a:hover {
  background: #3399ff;
}
section {
  background: #222;
  margin: 20px auto;
  padding: 20px;
  width: 90%;
  max-width: 800px;
  border-radius: 5px;
  border-left: 3px solid #ff0;
  font-size: 1.1em;
  transition: all 0.3s;
}
body.light section {
  background: #fff;
  border-left: 3px solid #0066cc;
}
.retro-heading {
  font-size: 1.2em;
  color: #ff0;
  margin-bottom: 15px;
  transition: all 0.3s;
}
body.light .retro-heading {
  color: #0066cc;
}
ul {
  text-align: left;
  padding-left: 40px;
}
.content-link {
  color: #ff0;
  transition: all 0.3s;
}
body.light .content-link {
  color: #0066cc;
}
.content-link:hover {
  text-decoration: underline;
}
footer {
  text-align: center;
  padding: 15px;
  background: #000;
  font-size: 1em;
  color: #aaa;
  transition: all 0.3s;
}
body.light footer {
  background: #1a2a4f;
  color: #fff;
}
footer a {
  color: #aaa;
  text-decoration: underline;
}
body.light footer a {
  color: #fff;
}
.theme-toggle {
  position: absolute;
  top: 10px;
  right: 15px;
  font-family: Courier, monospace;
  background: #444;
  color: #fff;
  border: none;
  padding: 5px 10px;
  border-radius: 5px;
  cursor: pointer;
  transition: all 0.3s;
}
body.light .theme-toggle {
  background: #aaa;
  color: #000;
}