I am attempting to create something short.com/ASWi7 -> short.com/index.php?h=ASWi7

and so i attempted by using this code on my small htaccess

RewriteEngine on
RewriteCond %{REQUEST_URI}  !^/index.php
RewriteRule ^(.*)$ /index.php?hash=$1   [L]

however the website manages to lose the css and everything...i organized my website in folder etc... so how do i exclude all of the folders or cetain files to participate that rule?

Try the next:

RewriteEngine on

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI}  !^/index.php
RewriteRule ^(.*)$ /index.php?hash=$1   [L]

!-f inspections for existing files

!-d inspections for existing sites

Hope that can help.