body {
  font-family: Arial, sans-serif;
  background: #f0f0f0;
  display: flex;
  justify-content: center;
  padding: 40px;
}
.container {
  background: #fff;
  padding: 20px;
  border-radius: 12px;
  max-width: 400px;
  width: 100%;
  box-shadow: 0 0 10px rgba(0,0,0,0.1);
}
label, input, select, button {
  display: block;
  width: 100%;
  margin-top: 12px;
  padding: 8px;
}
.result {
  margin-top: 20px;
  font-size: 20px;
  font-weight: bold;
}