<style>
    form{box-shadow:0 0 5px silver;padding:25px;margin-top:50px;margin-bottom:50px;}
    .scanner-input{width:100%;padding:10px;border:1px solid;}
    
    .send-message-btn{padding:10px;background:#E2E2E3;width:100%;border-radius:5px;border:none;margin-top:20px;}
    .send-message-btn:hover{background:#17376E;color:#fff;}
    .scanner-input:focus{outline:1px solid;}
</style>
<?php 
if(isset($_POST['scan_barcode'])){
    echo $userid=$_POST['userid'];
}
?>
<div class="container bg-white">
    <div class="row">
        <div class="col-sm-4">
            
        </div>
        <div class="col-sm-4 pt-3 pb-3">
            <form method="post" action="#">
                <label>Scan Bar Code</label>
                <input type="text" name="userid" class="scanner-input" placeholder="Scan Barcode">
                <input type="submit" name="scan_barcode" value="submit" class="send-message-btn">
            </form>
        </div>
        <div class="col-sm-4"></div>
    </div>
    
</div>