Redirection works but cannot load .css - .htaccess

Question

Hello.
I have a site protected by a .htaccess which redirects everything to the /pb directory except the /cron directory which is directly accessible (later it will be protected).
My htaccess works (it redirects as I want) BUT I cannot load the .css .js files that I call directly into my index page.
Do I have to put a new .htaccess in my /pb directory to allow access to .css or can I do it in my root htaccess ? I do not understand.
My .htaccess file (the https lines can't be removed "hostinger")
RewriteEngine on
RewriteCond %{HTTPS} off
RewriteCond %{HTTP_HOST} (www\.)?XXXXXXXXX.net
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]
RewriteRule ^(cron) - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^pb/ - [L]
RewriteCond %{DOCUMENT_ROOT}/pb/$1 -f
RewriteRule (.+) pb/$1 [L]
RewriteRule (.*) pb/index.php?path=$1 [L,QSA]
order deny,allow
deny from all
allow from XX.XXX.XXX.XX
Thanks for your help

Answer 1

First thing first, I have fixed your htacces rules file, comments have been made inside Rules file. Have your htaccess rules file like as follows style, make sure its placed in same folder where pb folder is there. Also please do clear your browser cache before testing your URLs.
Options -Indexes -MultiViews
RewriteEngine on
##Apply https rules here.
RewriteCond %{HTTPS} off
RewriteCond %{HTTP_HOST} ^(?:www\.)?XXXXXXXXX.net [NC]
RewriteRule ^ https://%{HTTP_HOST}%{REQUEST_URI} [NE,L,R=301]
##Handling base URI of site.
RewriteRule ^/?$ pb/ [R=301,L]
##Blocking pb uri pages non existing ones.
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^pb/ - [NC,L]
##making all uris which are files to pb folder.
RewriteCond %{DOCUMENT_ROOT}/pb/$1 -f
RewriteRule ^(.+)/?$ pb/$1 [L]
##Making non existing uris to index.php
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)/?$ pb/index.php?path=$1 [L,QSA]
order deny,allow
deny from all
allow from XX.XXX.XXX.XX
JS/CS rewrite/redirect:
You may need to use base tag to fix your js and other relative resources. If you are linking js files using a relative path then the file will obviously get a 404 because its looking for URL path. for example if the URL path is /file/ instead of file.html then your relative resources are loading from /file/ which is not a directory but rewritten html file. To fix this make your links absolute or use base tag. In the header of your webpage add this <base href="/"> so that your relative links can load from the correct location.