You can include a CSS style website broadly in the header code in the left menu via settings, website ui and header and footer.
For a website you can include a CSS style via the Rich Text or via Embed widget.
I prefer to answer general questions that everyone can take advantage of in the forum so that everyone can learn from the questions and the solutions provided.
For very specific questions where you do not want to post certain security and / or business matters in the forum, you can protect yourself by sending me a Personal Message (PM).