Menu Folder Horizontal Rule

Site URL: https://gerbercont.squarespace.com

Hello, I am trying to achieve an underlined affected underneath each item in the main navigation folder. I would like to have a horizontal rule underneath each item, but cannot seem to get the right effect with the text-decoration css that I am using right now. Is this even possible to achieve? I am using the Brine template and the website can be accessed here: https://gerbercont.squarespace.com with the password being "gerbercontrols". Below is what the desired appearance is in terms of the horizontal rule that I would like to have.

Add to Home > Design >

span.Header-nav-folder {
    border-top: 5px solid blue;
    padding: 0;
}
a.Header-nav-folder-item {
    text-decoration: none;
    padding: 10px;
    border-bottom: 1px solid #ededed !important;
}

Custom CSS

7 hours ago, tuanphan said:

Add to Home > Design >

span.Header-nav-folder {
    border-top: 5px solid blue;
    padding: 0;
}
a.Header-nav-folder-item {
    text-decoration: none;
    padding: 10px;
    border-bottom: 1px solid #ededed !important;
}

This works perfectly! Thank you very much for your help!