body {
  font-family: sans-serif;
  padding: 20px;
  background: #f9f9f9;
}
form input {
  margin: 5px;
  padding: 8px;
}
button {
  padding: 8px 12px;
  background: #0078d4;
  color: white;
  border: none;
  cursor: pointer;
}
#preview img {
  max-width: 200px;
  margin-top: 10px;
}
#lista-productos li {
  margin: 10px 0;
}