body {
  margin: 0;
  padding: 0;
  background: #f1f5f9;
  font-family: Arial, sans-serif;
}

.container {
  max-width: 420px;     /* ⬅️ ini kunci mobile enak */
  margin: 0 auto;       /* ⬅️ bikin ketengah */
  padding: 20px;
  background: #ffffff;
  min-height: 100vh;
}

h2 {
  text-align: center;
  margin-bottom: 20px;
}

label {
  font-weight: bold;
  display: block;
  margin-bottom: 5px;
}

select,
input,
button {
  width: 100%;
  padding: 12px;
  font-size: 16px;
  border-radius: 8px;
  border: 1px solid #ccc;
  box-sizing: border-box;
}

button {
  background: #1e40af;
  color: #fff;
  border: none;
  font-weight: bold;
}

button:active {
  transform: scale(0.98);
}

#hasil {
  margin-top: 15px;
}