Page URL named css or js doesn't work - .htaccess

Question

In my site when I go to URL such as my-site.com/css or my-site.com/js, then browser displays the folder listing instead of the actual page saved in the database. If I use Options All -Indexes in my htaccess then it says forbidden. I have following rule in my htaccess to load any dynamic page:
RewriteRule ^(.*)$ page.php?url=$1 [QSA,L]
Since I have also folders named css and js in my project, so I think server displays the directory content instead of dynamic page. How can I prevent this conflict. I know if I use a suffix "page" before my page name then it can be sorted out but i don't want to use any parameter before the page url.
EDIT
Here's my complete htaccess file:
# my-site.com
Options +FollowSymlinks -MultiViews
#RewriteBase /
#Enable mod rewrite
RewriteEngine On
DirectorySlash off
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^([^/]+)$ page.php?category=$1 [QSA,L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)/([^/]+)$ page.php?category=$1&post=$2 [QSA,L]

Answer 1

Since /js and /css are real directories your rewrite rules don't execute because you have this condition:
RewriteCond %{REQUEST_FILENAME} !-d
which means don't run for directories.
You can tweak your .htaccess to this:
Options +FollowSymlinks -MultiViews
RewriteEngine On
# add a trailing slash to directories
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule !/$ %{REQUEST_URI}/ [L,R=302]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^/]+)/?$ page.php?category=$1 [QSA,L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^/]+)/([^/]+)/?$ page.php?category=$1&post=$2 [QSA,L]