I have the following friendly url
RewriteRule ^noticias/([0-9]+)/?$ inicio.php?pg=noticias&id=$1
But when I access mysite.com/news/14
It changes the links of the files to
noticias/css/principal.css
where the original is
/css/principal.css
And when I access the link without the friendly example url
meusite.com.br/inicio.php?pg=noticias&id=$1
It works perfectly.
Your CSS should have a relative path and will be interpreted from the last page address bar
<link rel="stylesheet" href="css/principal.css"/>
This way depending on which page to open the address can be interpreted in different ways:
http://meusite.com.br/noticias/css/principal.css http://meusite.com.br/css/principal.css To work around the problem there are two solutions:
<link rel="stylesheet" href="http://meusite.com.br/css/principal.css"/>
<base>
To set the base reference of all links (CSS, JS, links and images)
<base href="http://meusite.com.br/"/>
In this way, all relative paths will not depend on the page address.
You are currently inserting your CSS file in a relative way, ie:
<link rel="stylesheet" href="/css/principal.css">
But in cases of friendly URL you should put CSS (and other assets like js and images) using an absolute path, which in this case would look like this:
<link rel="stylesheet" href="http://meusite.com.br/css/principal.css">
This is because the browser will understand the friendly URL as a directory, and will end up looking for the CSS inside that directory that does not exist ...