body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 20px;
  background-color: #f5f5f5;
}

header, footer {
  background-color: #1e1e2f;
  color: white;
  padding: 15px;
  text-align: center;
}

nav a {
  margin: 0 10px;
  color: white;
  text-decoration: none;
}

main {
  background-color: white;
  padding: 20px;
  border-radius: 8px;
}

label {
  display: block;
  margin-top: 10px;
}

.simulacion-box {
  border: 1px solid #ccc;
  height: 200px;
  margin-top: 20px;
  background: #eee;
  text-align: center;
  line-height: 200px;
}