.htaccess does not load css and js

.htaccess does not load css and js

i have 2 blog files one is blogdetail.php and bloglist.php. What i want to
make is if someone enters on a link like this
http://mysite.com/blog
to open bloglist.php and when someone enters to
http://mysite.com/blog/7
to open blogdetail.php?id=7. My .htaccess so far looks like this
Options +FollowSymLinks
RewriteEngine On
RewriteRule ^blog/([0-9]+)$ blogdetail.php?id=$1 [NC,L]
RewriteRule ^([a-zA-Z]+)$ $1.php [NC,L]
ErrorDocument 404 /404.php
but the problem is when i enter on blog/7 , the page opens but the css
does not load. Is there a way to make this work without using absolute
paths to css and js? Thank you, Daniel!