body {
  font-family: Arial, sans-serif;
  background: #111;
  color: #eee;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}
.container {
  width: 400px;
  padding: 20px;
  background: #222;
  border-radius: 10px;
  box-shadow: 0 0 10px #333;
}
input, select, button {
  width: 100%;
  padding: 10px;
  margin: 10px 0;
  border: none;
  border-radius: 5px;
}
button {
  background: #28a745;
  color: white;
  cursor: pointer;
}
#result {
  margin-top: 20px;
  font-weight: bold;
}