Current warning message is raised in brower console :
Resource interpreted as Stylesheet but transferred with MIME type text/plain: "https://unpkg.com/botui/build/botui.min.css".
The same error applies for Resource interpreted as Stylesheet but transferred with MIME type text/plain: "https://unpkg.com/botui/build/botui-theme-default.css".
It does not seems to affect the behavior of the website, so this is not an urgent bug to fix