this type="text/css">@import url('menu/menu_style.css"');</style
means load the css file inside the menu subfolder of the current folder
doesnt work when you are in a subfolder because the menu folder is no longer a subfolder
<style type="text/css">@import url('/menu/menu_style.css"');</style>
<style type="text/css">@import url('http://www.yoursite.com/menu/menu_style.css');</style>
<style type="text/css">@import url("<?php echo $_server['document_root']; ?>/menu/menu_style.css");</style>
<link rel="stylesheet" type="text/css" href="http://www.yoursite.com/menu/menu_style.css">
<link rel="stylesheet" type="text/css" href="<?php echo $_server['document_root']; ?>/menu/menu_style.css">
<link rel="stylesheet" type="text/css" href="/menu/menu_style.css">
all work
take your pick