admin_header.php

<?php
   if(isset($message)){
    foreach($message as $message){
        //  The period (.) is the concatenation operator in PHP. It is used to concatenate strings together. In this context,
        //  its used to concatenate the HTML markup and the message stored in the $message variable
        echo '
        <div class="message">
           <span>'.$message.'</span>
           <i class="fas fa-times" onclick="this.parentElement.remove()"></i>
        </div>
         ';
    }
   }
?>
 
<header class="header">
   <div class="flex">
       <a href="admin_page.php" class="logo">Admin<span>Panel</span></a>
        
       <nav class="navbar">
        <a href="admin_page.php">home</a>
        <a href="admin_products.php">products</a>
        <a href="admin_orders.php">orders</a>
        <a href="admin_users.php">users</a>
        <a href="admin_contacts.php">messages</a>
       </nav>

       <div class="icons">
         <div id="menu-btn" class="fas fa-bars"></div>
         <div id="user-btn" class="fas fa-user"></div>
       </div>

       <div class="account-box">
        <p>username: <span><?php echo $_SESSION['admin_name'];?></span></p>
        <p>email: <span><?php echo $_SESSION['admin_email'];?></span></p>
        <a href="logout.php" class="delete-btn">logout</a>
       </div>

   </div>

</header>