Sign In window - customize

[JakubMadej]

Hi

I would like to customize the Sign in window in WebAppBuilder (change the message, window color, font size, etc.). I've looked for some hints from https://community.esri.com/t5/arcgis-api-for-javascript-questions/cant-override-signin-dialog-on-3-1... and https://community.esri.com/t5/arcgis-api-for-javascript-questions/esrisignindialog/m-p/451543 . I’ve hidden serverLink and restLink but I don’t know where to change the message “Please sign in to access the item on”. Can anyone tell me in which file I have to change this?

My SingIn window below

Thanks