php mvc找不到css表因为url中的结尾斜杠

I just ran into a weird problem that I hope someone can help me with. Well, im using a mvc framework with my php project (first time), but it can't locate my css stylesheet from the different views if the URL is ending with a "normal slash" (/).

I have a Bootstrap class for handling this (deleting ending slashes):

$url = isset($_GET ['url']) ? $_GET['url'] : null;
$url = rtrim ( $url, '/');
$url = explode ( '/', $url );

But this doesn't seem to help regarding the stylesheet. The weird part is, when I try to print out $url, it doesn't have slash at the end, but still my views can't find it when there is one or more slashes in the end..

I found a "solution" if there is one slash at the end

<!doctype html>
<html>
<head>
    <title>'.$title.'</title>
    <link rel="stylesheet" href="public/css/stylesheet.css" />
    <link rel="stylesheet" href="../public/css/stylesheet.css" />
</head>
<body>

But then if my url has 2 slashes (help//) it doesn't work. Adding "../" before the path to the css sheet is a bad solution.. does anyone have any suggestions or ideas on how to REALLY trim the slashes from the $url?

Any help would be greatly appreciated.