issue in writing vhost

mydomainI created my WP blog in a /wordpress directory ( /var/www/html/wordpress ) Initially I created an .htaccess file to add /wordpress to the URI request

        <IfModule mod_rewrite.c>
    # Turn on rewrites.
    RewriteEngine on

    # Don't apply to URLs that go to existing files or folders.
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d

    # Only apply to URLs that aren't already under /wp.
    RewriteCond %{REQUEST_URI} !^/wordpress/

    # Rewrite all those to insert /wordpress
    RewriteRule ^(.*)$ /wordpress/$1

    # Redirect the root folder.
    RewriteCond %{HTTP_HOST} ^(www.)?mydomain.net$
    RewriteRule ^(/)?$ wordpress/ [L]
    </IfModule>

it was running fine .. can request mydomain.net or www.mydomain.net and reach my WP blog

As I want to add subdomains ( sub1.mydomain.net , sub2.mydomain.net ) I need to remove the .htaccess ( ? not sure) and add a mydomain-vhost.conf file

First I tried to write it only for my WP blog , I can access it but wo any CSS ...

NameVirtualHost *:80

<VirtualHost *:80>
        ServerAdmin myself@me.com
        ServerName mydomain.net
        ServerAlias www.mydomain.net

        DocumentRoot /var/www/html/wordpress
        <Directory />
                Options FollowSymLinks
                AllowOverride None
        </Directory>
        <Directory /var/www/html/wordpress>
                Options Indexes FollowSymLinks MultiViews
                AllowOverride None
                Order allow,deny
                allow from all
        </Directory>
</VirtualHost>

why no theme ?