setting background color to white makes line in progress bar invisible

My form looks like this:

After setting container to:

<div class="container" style="background:white;">

How i can make it on white and this progress bar line visible?

CSS: 

    https://pastebin.com/0hnUjRm7

HTML: 

    https://pastebin.com/Wc2zWkiJ

Do you have any ideas?

>Solution :

Add css file in #progressbar li property to z-index: 1; like this;

#progressbar li {
    list-style-type: none;
    font-size: 15px;
    width: 20%;
    float: left;
    position: relative;
    font-weight: 400;
    z-index: 1;
}