.hi-card {
  max-width: 520px;
  margin: 30px auto;
  padding: 24px;
  border-radius: 16px;
  background: linear-gradient(180deg, #f0f9ff, #ffffff);
  box-shadow: 0 10px 25px rgba(0,0,0,0.1);
  font-family: system-ui, sans-serif;
}

.hi-card h1 {
  text-align: center;
}

label {
  font-weight: 600;
  margin-top: 12px;
  display: block;
}

input {
  width: 100%;
  padding: 10px;
  margin-top: 4px;
  border-radius: 8px;
  border: 1px solid #ccc;
}

button {
  width: 100%;
  margin-top: 18px;
  padding: 14px;
  background: #0ea5e9;
  color: white;
  border: none;
  border-radius: 10px;
  font-size: 16px;
  cursor: pointer;
}

button:hover {
  background: #0369a1;
}

#result {
  margin-top: 20px;
  background: #f8fafc;
  padding: 15px;
  border-radius: 10px;
}

.note {
  font-size: 12px;
  color: #555;
  margin-top: 10px;
  display: block;
}