导航栏下拉列表不会出现

In my website I have created a NavBar file and I include it, with php, in every other php file I want. Now my navbar file has a dropdown inside:

.dropdown .dropbtn {
  font-size: 16px;
  border: none;
  outline: none;
  color: white;
  padding: 14px 16px;
  background-color: inherit;
  font-family: inherit;
  margin: 0;
  cursor: pointer;
}

.dropdown-content {
  display: none;
  position: absolute;
  background-color: white;
  min-width: 160px;
  box-shadow: white;
  z-index: 1;
  cursor: pointer;
}

.dropdown-inbuttons {
  border: none;
  padding: 6px 12px;
  text-decoration: none;
  display: inline-block;
  cursor: pointer;
  background-color: white;
  color: black;
}

.dropdown {
  position: relative;
  display: inline-block;
}

.dropdown-content {
  display: none;
  position: absolute;
  right: 0;
  background-color: white;
  min-width: 160px;
  box-shadow: white;
  z-index: 1;
  cursor: pointer;
}

.dropdown-content a {
  color: black;
  padding: 12px 16px;
  text-decoration: none;
  display: block;
}

.dropdown:hover .dropdown-content {
  display: block;
}

<link rel="stylesheet" href="https://www.w3schools.com/w3css/4/w3.css">
<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Roboto">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">


<div class="w3-top">
  <div class="w3-bar w3-black w3-card" style="height: 58px">
    <!-- Give attension here -->
    //.....other code....//
    <div class="dropdown" style="margin-top: 6px;">
      <button class="dropbtn">
              <i class="fa fa-caret-down"></i>
            </button>
      <div class="dropdown-content">
        <a href="#">Link 1</a>
        <a href="#">Link 2</a>
        <a href="../../../../registration/_includes/logout-system.php">Log Out</a>
      </div>
    </div>
  </div>

</div>

When I put my mouse up to the dropbtn it shows me this:

I know why this happen because the dropdown content is inside the navbar and in the code navbar height = 58px and doesn't fit. So How to make my dropdown visible front of the other html files?

I import the navbar in other php files with this way:

<html>
    <?php
    session_start();

    if(!isset($_SESSION['u_id'])){ 
    header("Location: ../../login.php");
    }
    include '../../_includes/server.php';
    $userid = $_SESSION['u_id'];
    $usersql = "SELECT * FROM `users` WHERE id='$userid'";
    $result = mysqli_query($conn, $usersql);
    if($row = mysqli_fetch_assoc($result))
    {
        $_SESSION['first_name'] = $row['first_name'];
        $_SESSION['last_name'] = $row['last_name'];
        include('../../../navBar/navBarConnected.php'); <!-- Here I include it-->
    }
    <head>...</head>
    <body>...</body>
</html>

</div>

First approach: Override overflow:hidden of .w3-bar by overflow:visible.

Second approach: Change position: relative of .dropdown class to position: static and wrap the <div class="dropdown">...</div> to another div and add position: relative to that.

Both of them will work. Choose whatever suits you.

.dropbtn {
    background-color: transparent;
    color: #fff;
    padding: 16px;
    font-size: 16px;
    border: none;
}

.dropdown {
    position: relative;
    display: inline-block;
}

.dropdown-content {
    display: none;
    position: absolute;
    background-color: #f1f1f1;
    min-width: 160px;
    box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
    z-index: 1;
}

.dropdown-content a {
    color: black;
    padding: 12px 16px;
    text-decoration: none;
    display: block;
}
.bar {
    background: black;
    color: #fff;
}

.dropdown-content a:hover {background-color: #ddd;}

.dropdown:hover .dropdown-content {display: block;}

.dropdown:hover .dropbtn {background-color: transparent;}

<link rel="stylesheet" href="https://www.w3schools.com/w3css/4/w3.css">
<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Roboto">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">


  
  <div class="bar">
  //.....other code....//
<div class="dropdown">
  <button class="dropbtn"><i class="fa fa-caret-down"></i></button>

  <div class="dropdown-content">
    <a href="#">Link 1</a>
    <a href="#">Link 2</a>
    <a href="#">Link 3</a>
  </div>
</div>
 </div>
 </div>

</div>