body {
  font-family: Arial, sans-serif;
  background: #ffffff;
  padding: 20px;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  margin: 0;
}

.container {
  background: white;
  border-radius: 10px;
  padding: 30px;
  max-width: 400px;
  width: 100%;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

h1 {
  text-align: center;
  color: #333;
}

.converter input,
.converter select,
.converter button {
  width: 100%;
  margin-top: 10px;
  padding: 10px;
  font-size: 1rem;
  border-radius: 5px;
  border: 1px solid #ccc;
}

.converter button {
  background: #4CAF50;
  color: white;
  cursor: pointer;
  border: none;
}

.converter button:hover {
  background: #45a049;
}

.converter #result {
  margin-top: 20px;
  font-weight: bold;
  text-align: center;
}

#history {
  margin-top: 20px;
  font-size: 0.9rem;
  color: #555;
}