body {
  font-family: Arial, sans-serif;
  background: linear-gradient(135deg, #667eea, #764ba2);
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0;
}

.container {
  background: white;
  padding: 30px;
  border-radius: 20px;
  text-align: center;
  width: 320px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.2);
}

#soal {
  font-size: 24px;
  margin: 20px 0;
}

input {
  width: 80%;
  padding: 10px;
  font-size: 18px;
  border-radius: 10px;
  border: 2px solid #ddd;
  text-align: center;
}

#hasil {
  margin-top: 15px;
  font-weight: bold;
}

button {
  display: none;
  margin-top: 20px;
  padding: 12px 20px;
  border: none;
  border-radius: 10px;
  background: #667eea;
  color: white;
  font-size: 16px;
  cursor: pointer;
  transition: 0.3s;
}

button:hover {
  background: #5a67d8;
}