How do I structure my .htaccess file(s)—using Kirby?

Hi. I’m using Kirby, which comes with a standard .htaccess file. I’ve enabled .htaccess through editing /etc/apache2/apache2.conf, but I think my .htaccess is not working. (I have enabled mod_rewrite with a2enmod rewrite.)

My folder structure is as follows:

|-/var
|-|-/www
|-|-|-/domain.com
|-|-|-|-.htaccess
|-|-|-|-index.php
|-|-|-|-/kirby
|-|-|-|-other (kirby) stuff

The relevant rewrite rules are:

<IfModule mod_rewrite.c>
RewriteEngine on
RewriteRule ^content/(.*)\.(txt|md|mdown)$ error [R=301,L]
RewriteRule ^site/(.*) error [R=301,L]
RewriteRule ^kirby/(.*) error [R=301,L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^panel/(.*) panel/index.php [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*) index.php [L]
</IfModule>

I am getting a 403 error when visiting my site: cool-house.nl.

What should I change to make things work as intended? Should I place another .htaccess file in /var/www?

Many thanks in advance!