body {
  font-family: Arial, sans-serif;
  background-color: #f4f4f4;
  text-align: center;
  padding: 40px;
}
.container {
  background: #fff;
  padding: 20px;
  max-width: 400px;
  margin: 0 auto;
  border-radius: 10px;
  box-shadow: 0 0 10px rgba(0,0,0,0.1);
}
input[type="text"] {
  width: 80%;
  padding: 10px;
  margin-bottom: 10px;
}
button {
  padding: 10px 20px;
  cursor: pointer;
}
#result {
  margin-top: 20px;
  font-weight: bold;
}