I'm in Linux, Elementary OS, and installed lampp in opt.
My CSS and JS won't load. When I inspect my page through browser. The console says Failed to load resource: the server responded with a status of 403 (Forbidden) I'm really sure that my directories are correct.
This is the error
You need to change permissions on the folder bootstrap/css. Your super user may be able to access it but it doesn't mean apache or nginx have access to it, that's why you still need to change the permissions.
Tip: I usually make the apache/nginx's user group owner of that kind of folders and give 775 permission to it.