Incrementing menu levels

I'm trying create a page that displays a multi level menu.

For example my menu looks like this

Home
About
Product
    - Watches
        - Rolex
        - Some other watch
    - Tops
    - Pants
Contact

As you can see it has more then 2 levels. What I'm trying to do is find out what level I'm on so that I can style it accordingly.

So for example Home, About, Product, Contact would be level 1, Watches, Tops, Pants would be level 2 and Rolex, Some other watch would be level 3.

I would like to do this dynamically so that if I ended up having even more levels I can then style as needed. At the moment my code isn't incrementing how I would like it

This is my code

function admin_menus($parent_id = 0, $level = 1)
{
    global $conn;

    $query = "SELECT * FROM menus WHERE parent_id = ".$parent_id;
    $menus = mysqli_query($conn, $query);
    confirmQuery($menus);

    // Checks to see if there is any rows in the table
    if(mysqli_num_rows($menus) > 0)
    {
        while($row = mysqli_fetch_assoc($menus))
        {
            $menu_id = $row['id'];
            $menu_title = $row['title'];
            $menu_position = $row['position'];

            if($parent_id > 0)
            {
                $sub_menu = "sub-menu";
                $sub_icon = "<i class='fa fa-angle-right pr-10'></i>";
            }else{
                $sub_menu = "";
                $sub_icon = "";
            }

            echo "<tr class='$level' data-index='$menu_id' data-position='$menu_position'>";
            echo    "<td>";
            echo        "<div class='$sub_menu'>";
            echo            $sub_icon;
            echo            "<a href='menus.php?source=edit_menu&m_id=$menu_id'>";
            echo                $menu_title;
            echo            "</a>";
            echo        "</div>";
            echo    "</td>";

            echo    "<td>";
            echo        "<div class='dropdown text-center'>";
            echo            "<button class='btn btn-sm btn-primary dropdown-toggle' type='button' id='dropdownActionButton' data-toggle='dropdown' aria-haspop='true' aria-expanded='false'>";
            echo                "<i class='fa fa-cogs'></i>";
            echo            "</button>";

            echo            "<div class='dropdown-menu dropdown-menu-right' aria-labelledby='dropdownActionButton'>";
            echo                "<a href='menus.php?source=edit_menu&m_id=$menu_id' class='dropdown-item'>";
            echo                    "Edit";
            echo                "</a>";

            echo                "<a href='menus.php?delete=$menu_id' class='dropdown-item'>";
            echo                    "Delete";
            echo                "</a>";
            echo            "</div>";
            echo        "</div>";
            echo    "</td>";
            echo "</tr>";

            // Increments the level
            $multi_level = $level++;

            admin_menus($menu_id, $level);
        }
    }
}