body {
  font-family: sans-serif;
  text-align: center;
  padding: 20px;
  transition: background-color 0.3s;
}

#reader {
  width: 300px;
  margin: auto;
}

#status {
  margin: 15px;
  font-weight: bold;
}

#log {
  background: #eee;
  padding: 10px;
  margin: 10px auto;
  width: 90%;
  max-height: 200px;
  overflow-y: auto;
  text-align: left;
  font-size: 0.9em;
}

button {
  margin: 5px;
  padding: 10px 15px;
  font-size: 1em;
}