#sms-checker-ui { position: relative; min-height: 0; }
#sms-checker-ui .btn-block, #sms-checker-ui .input-group { width: 100%; }
#sms-checker-ui .sms-feedback { position:absolute; left:0; right:0; top:100%; margin-top:4px; font-size:11px; line-height:1.3; }
#sms-success.sms-feedback { color:#3c763d; text-align: center; }
#sms-error.sms-feedback   { color:#a94442; text-align: center; }
.alert-validation { font-size:11px; }

/* Optional: make input full width when verified */
.sms-verified-full .col-sm-7, .sms-verified-full .col-sm-8 { float:none; width:100% !important; }
.sms-verified-full .col-sm-5, .sms-verified-full .col-sm-4 { display:none !important; }