如何使菜单导航栏或子菜单根据我打开的页面着色？我使用config来设置链接页面。

<li class="nav-item dropdown active"><a class="nav-link" href="<?php echo $base_url.'index.php?page=home'; ?>">Home</a></li>

                      <li class="nav-item dropdown">
                          <a href="#" class="nav-link dropdown-toggle" data-toggle="dropdown">Data <i class="fa fa-angle-down"></i></a>
                          <ul class="dropdown-menu" role="menu">
                            <li><a href="<?php echo $base_url.'index.php?page=importdata'; ?>">Import Data</a></li>
                            <li><a href="<?php echo $base_url.'index.php?page=importdata'; ?>">Input Data</a></li>
                          </ul>
                      </li>
              
                      <li class="nav-item dropdown">
                          <a href="#" class="nav-link dropdown-toggle" data-toggle="dropdown">MASTER <i class="fa fa-angle-down"></i></a>
                          <ul class="dropdown-menu" role="menu">
                            <li class="dropdown-submenu">
                                <a href="#!" class="dropdown-toggle" data-toggle="dropdown">Harian Proses</a>
                                <ul class="dropdown-menu">
                                <li><a class="dropdown-item" href="<?php echo $base_url.'index.php?page=HarianProsesIn'; ?>">IN</a></li>
                                <li><a class="dropdown-item" href="<?php echo $base_url.'index.php?page=HarianProsesOut'; ?>">OUT</a></li>
                                </ul>
                            </li>
                            <li><a class="dropdown-item" href="<?php echo $base_url.'index.php?page=worktime'; ?>">WORK TIME</a></li>
                            <li><a class="dropdown-item" href="<?php echo $base_url.'index.php?page=kapasitas'; ?>">KAPASITAS</a></li>
                            <li><a class="dropdown-item" href="<?php echo $base_url.'index.php?page=harga'; ?>">HARGA</a></li>
                            <li><a class="dropdown-item" href="<?php echo $base_url.'index.php?page=user'; ?>">USER</a></li>
                          </ul>
                      </li>

在哪里可以放置额外的代码，以便导航栏可以根据我当前打开的页面处于活动状态？

config.php

if(isset($_SESSION['username'])){
        switch($page){
            case 'login': // $page == login (jika isi dari $page adalah home)
            include "system/login.php"; // load file login.php yang ada di folder views
            break;
            
            case 'importdata': // $page == home (jika isi dari $page adalah home)
            include "views/importdata/importdata.php"; // load file home.php yang ada di folder views
            break;
            
            // laporan
            case 'LaporanRMPG01': // $page == home (jika isi dari $page adalah home)
            include "views/laporan/laporanrmpg_1.php"; // load file home.php yang ada di folder views
            break;

            default: // Ini untuk set default jika isi dari $page tidak ada
            // Set halaman 404 Not Found
            header("HTTP/1.0 404 Not Found");
            echo "<h1>404 Not Found</h1>";
            echo "The page that you have requested could not be found.";
            exit();
        }
}else // Jika belum login
    include "system/login.php"; // Set default halamannya adalah "login"
?>