style.css

.form {
  font-family: Helvetica, sans-serif;
  max-width: 400px;
  margin: 0 auto;
  padding: 16px;
  background: #f7f7f7;
}
.form h1 {
  background: #5868bf;
  padding: 20px 0;
  font-weight: 300;
  text-align: center;
  color: #fff;
  margin: -16px -16px 16px -16px;
  font-size:  25px;
}
.form input[type="text"],
.form input[type="url"] {
  box-sizing: border-box;
  width: 100%;
  background: #fff;
  margin-bottom: 4%;
  border: 1px solid #ccc;
  padding: 3%;
  color: #555;
}
.form input[type="text"]:focus,
.form input[type="url"]:focus {
  box-shadow: 0 0 5px #5868bf;
  padding: 3%;
  border: 1px solid #5868bf;
}

.form button {
  box-sizing: border-box;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  width: 150px;
  margin: 0 auto;
  padding: 3%;
  background: #5868bf;
  border-bottom: 2px solid #5868bf;
  border-top-style: none;
  border-right-style: none;
  border-left-style: none;
  color: #fff;
  cursor: pointer;
}
.form button:hover {
  background: rgba(88,104,191, 0.5);
}
#qrcode-container{
    display:none;
}

.qrcode{
  padding: 16px;
  
}
.qrcode img{
  margin: 0 auto;
}

.center {
  display: flex;
  justify-content: center;
  align-items: center;
}