I create a Popup like with blurred background like this
As you can see the popup card is suffering from other colors inside the card. I want the popup tag to be white and separated from the background. Here my code :

<div  id="popup">
    
        <label for="txtName">UserName:</label>
        <input type="text" id="txtName" class="form-control mb-2">
        <label for="txtAddress">Address:</label>
        <input type="text" id="txtAddress" class="form-control mb-2">
        <label for="txtPhone">Phone Number:</label>
        <input type="text" id="txtPhone" class="form-control mb-4">
        <button id="btnSave" class="btn btn-primary btn-block">Save</button>
        <button href="" class="close-btn" onclick="toggle()">×</button>
      
   
</div>
  <a class="primary-btn order-submit" style="cursor : pointer" onclick="toggle()" id="btnOpenPopup">Add New Address</a>
<style>
  
    .container#blur.active {
        filter : blur(20px);
        pointer-events : none;
        user-select : none;
    }
    #popup
    {
        position : fixed;
        top : 40%;
        left : 50%;
        transform : translate(-50%,-20%);
        width : 600px;
        padding : 50px;
        box-shadow : 0 5px 30px rgba(0,0,0,.30);
        background : #fff;
        visibility : hidden;
        opacity : 0;
        transition : 0.5s;
    }
    #popup .close-btn
    {
        position : absolute;
        top : 1px;
        right : 10px;
        
        height : 20px;
        background : #fff;
        color: #111;
        border : none;
        outline : none;
       
    }
    #popup.active
    {
        visibility : visible;
        opacity : 1;
        transition : 0.5s;
    }

</style>
<script type="text/javascript">

    function toggle() { 
        var blur = document.getElementById('blur');
        blur.classList.toggle('active')
        var popup = document.getElementById('popup');
        popup.classList.toggle('active')
    }
</script>

I notice when I scroll down the popup to the footer the popup tag turn to be like this img . Its seem like the popup transparent. Is there any way I can improve it?. Thank for your help