Well, I'm studying friendly urls and I came across a problem. Every time I put a / (slash) at the end of the url, the css disappears and the page gets pure html.
I'd like to understand what's going on and fix it. Follow the images below for a better understanding.
The best solution (depending on your application) is to use the base HTML5 tag.
<base href="http://seusite.com/" target="_blank">
See an example on the w3schools site.
Another method is to get the system root folder and play it at a constant. Since you have not shown which server side language you are using, I will show the example in PHP.
<?php
define("ROOT", __DIR__); //obtém pasta root
In your code you use
<img src="<?=ROOT?>/stickman.gif" width="24" height="39" alt="Stickman">
There are still a number of other examples, but I think these may be enough to heal your doubt and help you.