Including the CSS works imperfectly. If you need to, it's better to define
CSS styles for the snippet in the external website itself.
Preferred method of inclusion, if your external website can support a server-side include.
Last resort. If this is your only option, you can embed this HTML source directly into your external website.
However, if data or features change here, your snippet will not reflect those changes, and may even stop working.
Use with care.