body {
  font-family: Arial, sans-serif;
  background: #f9f9f9;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  margin: 0;
}

.container {
  background: #fff;
  padding: 20px 30px;
  border-radius: 10px;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
  max-width: 400px;
  width: 100%;
  text-align: center;
}

h1 {
  margin-bottom: 20px;
  font-size: 24px;
}

input[type="number"],
.result-box {
  margin: 10px 0;
  padding: 8px;
  width: 100%;
  border: 1px solid #ccc;
  border-radius: 5px;
}

.options {
  text-align: left;
  margin-bottom: 15px;
}

button {
  padding: 10px 20px;
  background-color: #4caf50;
  color: white;
  border: none;
  border-radius: 5px;
  cursor: pointer;
}

button:hover {
  background-color: #45a049;
}

.result-box {
  background-color: #f0f0f0;
  font-weight: bold;
}