Stats/header.php

<?php
session_start();
if(!isset($_SESSION['restaurant_user_id']))
{
    header("location: login.php");
    return;
}

include_once "database.php";
?>
<!DOCTYPE html>
<html lang="en">

<head>
    <title>Restaurant</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css">
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.6.4/jquery.min.js"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/js/bootstrap.min.js"></script>
    <style>
    /* Remove the navbar's default margin-bottom and rounded borders */
    .navbar {
        margin-bottom: 0;
        border-radius: 0;
    }

    /* Add a gray background color and some padding to the footer */
    footer {
        background-color: #f2f2f2;
        padding: 25px;
    }
    </style>
</head>

<body>

    <nav class="navbar navbar-inverse">
        <div class="container-fluid">
            <div class="navbar-header">
                <button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#myNavbar">
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                </button>
                <!-- <a class="navbar-brand" href="#">Logo</a> -->
            </div>
            <div class="collapse navbar-collapse" id="myNavbar">
                <ul class="nav navbar-nav">
                    <li class="active"><a href="index.php">Home</a></li>
                    <li><a href="zones.php">Zones</a></li>
                    <li><a href="tables.php">Tables</a></li>
                    <li><a href="servers.php">Servers</a></li>
                    <li><a href="guests.php">Guests</a></li>
                    <li><a href="bookings.php">Bookings</a></li>
                </ul>
                <ul class="nav navbar-nav navbar-right">
                    <li><a href="logout.php"><span class="glyphicon glyphicon-log-in"></span> Logout</a></li>
                </ul>
            </div>
        </div>
    </nav>


    <div class="container" style="min-height: 82vh;">