.height-30px {
    height: 30px;
}

.height-100px {
    height: 100px;
}

.group-qr-code {
    text-align: center;
}

.group-qr-code-caption {

    text-align: center;
}

.link-btn {
    margin-top: 30px;
}

.zzn-content {
    text-align: right;
}
.height-30px {
    height: 30px;
}

.height-100px {
    height: 100px;
}

.group-qr-code {
    text-align: center;
}

.group-qr-code-caption {

    text-align: center;
}

.link-btn {
    margin-top: 30px;
}

.zzn-content {
    text-align: right;
}

/* Overriding bootstrap */
.container {
    padding-right: 0px; /*15px in bootstrap.css*/
    padding-left: 0px;  /*idem*/
    margin-right: auto;
    margin-left: auto;
}

Remove left and right whitespace
Remove left and right whitespace
