Source code :
<?php 
   $act1="class='sidebar-item active'"; 
   $act2="class='sidebar-item'";
?>

<li <?php if($mnu=="home"){echo $act1;} else{echo $act2;}?> >
<a class="sidebar-link" href="index.php?mnu=home"><i class="align-middle" data-feather="home"></i> 
<span class="align-middle">Dashboard</span></a></li>
>