Typing as I listen, and straight off there is a real unique feel to this mix. A real clarity in all the parts and I like how you have really pushed back the feel of the synth. The bass is very much up front in the verse, but it works ok. Chorus comes in nicely, but I feel the strings really needed some more stringent automation, as some notes really jump out and others and drop off.
Your vocals sound great and I like how you have treated and balanced the backing vocals, especially in the verses. The drums sound pretty solid, but I feel like there should/could be a little more low end in the bass and kick to make the mix really thump more. Having said that, that may not have been your vision entirely and the mix is in no way harmed by the lack of low end, as both instruments can clearly be heard and are not masking each other!
Really, other than the strings being a little loose, I don't hear any issues with this mix. Perhaps, if anything, there could be some subtle changes made to make each transition or each section have greater impact, but really, to me, this is a mix that was very enjoyable to listen to. Awesome job!!!
Rules do not belong in music. Like food, there are flavours that work well together, but in the end, it's each person's taste that determines the quality of the meal.