body {
  font-family: Georgia, serif;
  background-color: #f7f7f7;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  margin: 0;
}

.converter-card {
  background: #ffffff;
  padding: 2rem;
  border-radius: 20px;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.08);
  text-align: center;
  max-width: 500px;
  width: 90%;
}

h1 {
  font-size: 1.8rem;
  margin-bottom: 1.4rem;
  line-height: 1.4;
}

.input-group {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  margin-bottom: 1rem;
}

input, select, button {
  padding: 10px 12px;
  font-size: 1rem;
  border-radius: 10px;
  border: 1px solid #ccc;
}

button#swapBtn {
  background-color: #007bff;
  color: white;
  border: none;
  cursor: pointer;
  transition: background-color 0.3s ease;
}

button#swapBtn:hover {
  background-color: #0056b3;
}

.result {
  margin-top: 1rem;
  font-size: 1.2rem;
  font-weight: bold;
}