I am not so certain that EU261 applies. Neither Croatia nor Swiss is a EU country. In this case, Swiss is only bound to EU261 through the Agreement between the European Community and the Swiss Confederation on Air Transport (sry, cannot link as a new user). Swiss wil argue that art. 15 of that Agreement limits the applicability of the agreement to flights between Swiss and the EU. Swiss' viewpoint has been challenged in Germany, but when a prejudiciary ruling of the ECJ was requested (Recinto-Pfingsten) Swiss promptly settled the case. Unless you are in Germany, you should expect a long legal battle.
Even if EU261 applies, it is not clear whether your flight got canceled or rerouted. Under strict application of EU261, a cancellation is required for compensation. Although you will point at the Sturgeon and Nelson cases, the aforementioned agreement contains a clause:
For this purpose, the provisions laid down in this Agreement as well as in the regulations and directives specified in the Annex shall apply under the condition set out hereafter. Insofar as they are identical in substance to corresponding rules of the EC Treaty and to acts adopted in application of that Treaty, those provisions shall, in their implementation and application, be interpreted in conformity with the relevant rulings and decisions of the Court of Justice and the Commission of the European Communities given prior to the date of signature of this Agreement.
EU261 was added to the Annex October 18, 2006 (again, cannot link to the decision). Therefore, EU261 should be interpreted according to the rulings at that time, without the widened interpretation ex Sturgeon/Nelson.