I'm not familial with CSL code, so I would be very grateful to have available the Harvard-like style (author-date) used in the journal "Epilepsia".

Here I report the official Epilepsia INSTRUCTIONS for AUTHORS (Wiley Periodicals, Inc):

Citation of references in the text of an article should be given by author last name (no initials) followed by the year.
When two or more citations are given, list them in chronological order. When there are two authors, include both names, separated by “&”; when there are three or more names, give only the first author followed by “et al.”
If there are two or more papers by the same author(s) in the same year, identify them by “a”, “b”, etc. (and be sure to include the identifying letters in the Reference List).
Arrange citations in alphabetical order by the first author’s last name; do not number the citations.
List all the authors (do not use “et al.” in the reference list).
When there are two or more references to the same author(s), list them in chronological order.
For journal references, the names of authors (last name and initials) should be followed by the date (in parentheses), title of the article, journal name (in italics – use PubMed abbreviations), volume number (followed by a colon) and pages (first – last page numbers).
Reference to electronic material should include author name(s), date, article title, and journal (as above); where volume and/or page numbers are not available, substitute Digital Object Identifier (DOI) number.
For book references, the names of authors should be followed by the date, the full title of the book (in italics), the publisher and the location of the publisher’s office.
For a chapter in a book, provide chapter authors, date, chapter title, book editors’ names, book title (italics), publisher, location of publisher’s office, and inclusive page
numbers.

Sample Journal References

Journal article in a print issue:
Salmenpera TM, Symms MR, Boulby PA, Barker GJ, Duncan JS (2006) Postictal diffusion weighted imaging. Epilepsy Res. 70:133-143.

Electronic reference:
Baxendale S, Thompson P, Harkness W, Duncan J (2007) The role of the intracarotid amobarbital procedure in predicting verbal memory decline after temporal lobe resection. Epilepsia Published online: 25-Jan-2007; doi: 10.1111/j.1528-1167.2006.00940.x

Book:
Shorvon S (2005) Handbook of the treatment of epilepsy. Blackwell Publishing, Oxford

Chapter in a book:
Wenzel HJ, Schwartzkroin PA (2006) Morphologic approaches to the characterization of epilepsy models. In Pitkanen A, Schwartzkroin PA, Moshe SL (eds) Models of seizures and epilepsy, Elsevier Academic Press, San Diego, pp. 629-652.