.htaccess clean URLs with slugs 404 not found - regex

Question

I apologize for asking this question once again, but I'm unable to make my URLs work without getting an 404 page error.
public_html
.htaccess
webroot+
index.php
article.php
I'm using htaccess to make the webroot folder the main document root ( I do not have access to virtual hosts)
RewriteCond %{HTTP_HOST} ^site.com$ [NC]
RewriteRule ^(.*)$ http://www.site.com/$1 [R=301,L]
RewriteCond %{REQUEST_URI} !webroot/
RewriteRule (.*) /webroot/$1 [L]
I'm not sure if the issue is caused due to the code above but when I try making my URLs clean for seo I get an 404 page.
I'm trying to change www.site.com/article.php?article_uid=number&article_title=title ---> www.site.com/article/id/title/
With the following code it allows the page to change the url but it gives me an 404 not found.
RewriteCond %{THE_REQUEST} \ /article\.php\?article_uid=([^&]+)&article_title=([^&\ ]+)
RewriteRule ^ /article/%1/%2/? [L,R=301,NE]
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^article/([^/]+)/([^/]+)/?$ /article.php?article_uid=$1&article_title=$2 [L,QSA]
ex.
The requested URL /webroot/article/id/title/ was not found on this server.

Answer 1

Change last rule to:
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule (?:^|/)article/([^/]+)/([^/]+)/?$ webroot/article.php?article_uid=$1&article_title=$2 [L,QSA]