/* (X) NOT IMPORTANT */
* {
  font-family: Arial, Helvetica, sans-serif;
  box-sizing: border-box;
  font-size: 1rem;
}
body, input, #demoNFC, #demoMSG { padding: 10px; }
body { max-width: 600px; }
#demoNFC {
  display: flex;
  margin-bottom: 10px;
  border: 1px solid #e7e7e7;
  background: #f3f3f3;
}
#demoT { flex-grow: 1; }
input {
  padding: 10px;
  border: 0;
}
input[type=button] {
  margin: 0 1px;
  color: #fff;
  background: #225cc5;
  cursor: pointer;
}
input[type=button]:disabled { 
  color: #7c7c7c;
  background: #c3c3c3;
}
#demoMSG {
  border: 1px solid #e7e7e7;
  background: #fff;
}