How to properly configure Yii2 to work on subdomains?

Question

Yii

All subdomains of the site lead to the main directory, but when you open a subdomain, everything works except for including styles.
That is:
site.ru/css/site.css - opens.
subdomain.site.ru/css/site.css - 404 error.
At the same time, bootstrap styles are connected normally.
Subdomains are implemented through links, that is, on hosting in the root folder there is a directory "subdomain.site.ru" which is a link to the directory "site.ru"
What rules or parameters are missing in the yii2 settings so that everything works correctly?

Answer 1

what yii2 are you using and is it possible to look at the config