lampromy

i think its quite easy in my case..

echo "<style>";
if($_GET['page_id']==10){
  echo "#sidebar {display:block;}";
}else{
  echo "#sidebar {display:none;}";
}
echo "</style>";
echo "<script type='text/javascript'>";
echo "document.getElementById('content').style.width='95%'";
echo "</script>";

If i know how you hide your side bat i can suggest something.
One more thing.. i used wordpress standard login page for client authentication. This code automatically takes on login page and return on requested page after successful login. You need to place below code on top of the page.

if(!function_exists(is_user_logged_in)){
  	  die('Sorry, You do not have access of this page.');
  }
  if ( !is_user_logged_in() ) {
	$returnPath = get_settings('siteurl') . '/wp-login.php?redirect_to=' . urlencode($_SERVER['REQUEST_URI']);
	echo "<script type='text/javascript'>";
	echo "window.location.href='$returnPath'";
	echo "</script>";
	exit();
  }