body {
  font-family: 'Segoe UI', sans-serif;
  background: #f5f7fa;
  margin: 0;
}

.container {
  max-width: 600px;
  margin: 40px auto;
  background: #fff;
  padding: 30px;
  border-radius: 10px;
  box-shadow: 0 5px 25px rgba(0,0,0,0.05);
}

h1 {
  color: #0077cc;
  text-align: center;
}

.subtitle {
  text-align: center;
  color: #666;
  margin-bottom: 25px;
}

label {
  margin-top: 10px;
  display: block;
  color: #333;
}

input {
  width: 100%;
  padding: 10px;
  font-size: 1rem;
  border-radius: 5px;
  border: 1px solid #ccc;
  margin-bottom: 15px;
}

button {
  width: 100%;
  padding: 12px;
  background-color: #0077cc;
  color: white;
  border: none;
  border-radius: 6px;
  font-size: 1rem;
  cursor: pointer;
}

button:hover {
  background-color: #005fa3;
}

.result {
  text-align: center;
  margin-top: 25px;
  font-size: 1.1rem;
  color: #333;
}

.tip {
  margin-top: 10px;
  color: #0077cc;
  font-weight: 600;
}