body {
  background-color: #e0e0e0;
}
body nav {
  display: flex;
  justify-content: center;
}
body nav a {
  margin: 0 15px;
  text-decoration: none;
  color: #3700ff;
  font-weight: bold;
  transition: color 0.3s;
}
body nav a:hover {
  color: #6200ea;
}
body main {
  font-family: "Courier New", Courier, monospace;
  width: 50%;
  margin: 0 auto;
  padding: 20px;
  background-color: #ffffff;
  color: #333;
  border: 1px solid #ccc;
  border-radius: 8px;
  height: 100vh;
}
body main img {
  margin-right: 10px;
}
body main marquee {
  color: #3700ff;
  font-weight: bold;
}
body main fieldset {
  margin-bottom: 20px;
  background-color: #f5f5f5;
}
body main fieldset dl dt {
  font-weight: bold;
  color: #3700ff;
  margin-bottom: 5px;
}
body main fieldset dl dd {
  margin-bottom: 10px;
  color: #555;
}