Why instagram page in sfsafariviewcontroller is so big?

Question

Here is my code to auth with Instagram using safariviewcontroller. Everything is okay, but web page in SFVC is too big, why?

    func doOAuthInstagram(_ serviceParameters: [String:String]){
        let oauthswift = OAuth2Swift(
            consumerKey:    serviceParameters["consumerKey"]!,
            consumerSecret: serviceParameters["consumerSecret"]!,
            authorizeUrl:   "https://api.instagram.com/oauth/authorize",
            responseType:   "code"
        )

        oauthswift.allowMissingStateCheck = true
        oauthswift.authorizeURLHandler = SafariURLHandler(viewController: self, oauthSwift: oauthswift)

        guard let rwURL = URL(string: "https://badyi.github.io/") else { return }

        oauthswift.authorize(withCallbackURL: rwURL, scope: "user_profile,user_media", state: "1"){ result in
                   switch result {
                   case .success(let (credential, _, _)):
                       self.showTokenAlert(name: serviceParameters["name"], credential: credential)
                   case .failure(let error):
                       print(error.description)
                   }
        }
    }

Result

Thanks in advance.