body {
  margin: 0;
  padding: 0;
  font-family: Arial, sans-serif;
  background: #f2f4f8;
  color: #222;
}

.container {
  max-width: 500px;
  margin: 40px auto;
  background: #ffffff;
  padding: 25px;
  border-radius: 8px;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

h1 {
  text-align: center;
  margin-bottom: 5px;
}

.subtitle {
  text-align: center;
  font-size: 14px;
  color: #555;
  margin-bottom: 20px;
}

.converter {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.row {
  display: flex;
  flex-direction: column;
}

label {
  font-size: 13px;
  margin-bottom: 4px;
}

input,
select {
  padding: 10px;
  font-size: 14px;
  border-radius: 4px;
  border: 1px solid #ccc;
}

button {
  margin-top: 10px;
  padding: 12px;
  background: #2c7be5;
  color: white;
  border: none;
  border-radius: 4px;
  cursor: pointer;
}

button:hover {
  background: #1a68d1;
}

.result {
  margin-top: 10px;
  padding: 10px;
  background: #f1f5ff;
  border-radius: 4px;
  text-align: center;
  font-weight: bold;
}

h2 {
  margin-top: 30px;
  font-size: 18px;
}

#historyList {
  list-style: none;
  padding: 0;
  max-height: 200px;
  overflow-y: auto;
}

#historyList li {
  font-size: 13px;
  padding: 6px;
  border-bottom: 1px solid #eee;
}

footer {
  text-align: center;
  font-size: 12px;
  color: #777;
  margin-top: 20px;
}