body {
  font-family: Arial, sans-serif;
  background-color: #f2f2f2;
  margin: 0;
  padding: 0;
}

.container {
  max-width: 600px;
  margin: 40px auto;
  background: white;
  padding: 30px;
  border-radius: 10px;
  box-shadow: 0 0 15px rgba(0, 0, 0, 0.1);
}

h1 {
  text-align: center;
}

select,
input {
  width: 100%;
  padding: 8px;
  margin-top: 10px;
  margin-bottom: 10px;
}

button {
  padding: 10px 15px;
  margin-right: 10px;
  cursor: pointer;
  border: none;
  border-radius: 5px;
  background-color: #2c7be5;
  color: white;
}

button:hover {
  background-color: #1a5fd0;
}

.botones {
  margin-top: 10px;
  margin-bottom: 20px;
}

ul {
  list-style: none;
  padding: 0;
}

li {
  padding: 5px 0;
  border-bottom: 1px solid #ddd;
}

#total {
  margin-top: 15px;
  font-weight: bold;
  font-size: 18px;
}

.error {
  color: red;
  font-size: 14px;
}