But there is the breed Russian Blue.....

There is Tom of course, from Tom and Jerry. :-)

I was surprised that it accepted "blue cats do not exist."

Yep, not exactly blue, but bluish gray? Well that's what they call blue when naming cat fur's color ;)

'No blue cats' can't be right translation in some context?

Yet...

Дораемон, пожалуйста читайте это. :-D

why Синих ? I do not understand that.

What about doraemon? He was a blue cat...

there are no dark blue cats

ok in one senstense сини is transleted like dark blue in other like blue. can you fix that problem ? it is really anoying

Может быть вы имели в виду Не бывать или не существуют