You can select encoding when "export records", so I guess you are talking about "export field contents".
So, you can save your .css file in same encoding (UTF-16LE) then it will work without changing HTML file format. You should write correct encoding if there is in the HTML.
Thank you for your quick reply!
there are several Ideas posted on this forum for improving the Export (and Import) to allow for better control of delimiter (column and row), header, and the encoding.
I wrote an article with some possible work-arounds, in the meantime: