h1,h4 {
  text-align: center;
}

#reader {
  width: 500px;
  margin: auto;
  justify-content: center;  
}

output{
  margin: auto;
  justify-content: center; 

}

.result {
  background-color: green;
  color: #fff;
  padding: 20px;
}

.row {
  display: flex;
}

#reader__scan_region {
  background: white;
}