How to process links in htaccess if there are 2 getas?

Question

Regular Expressions

How to configure second get requests via htaccess?
Here is the link before processing:
https://lastlegends.site/?page=register
Here is after processing:
https://lastlegends.site/register
RewriteRule ^([a-zA-Z0-9]+)$ ?page=$1
How to convert this link:
https://lastlegends.site/?page=register&referal=9
In :
https://lastlegends.site/register/referal9
and if you do this, will the styles not fly off?
Here on the page links to pages are processed in this way:

if(empty($_GET['page'])){
  $page = 'index';
}else{
  $page = preg_replace("/[^a-zA-Z0-9]/", "", $_GET['page']);
}
//И далее идет на получение файла страницы...

Answer 1

RewriteEngine On
RewriteRule ^([a-zA-Z0-9]+)$ ?page=$1
RewriteRule ^([a-zA-Z0-9]+)/([a-zA-Z0-9]+)$ ? page=$1&referral=$2