I don't think anyone expected such a result in Croatia's match against Turkey. After all, the Croats seemed to be the favorites, they played at a new stadium, at home, the balance of goals scored and conceded was excellent, the largest in the group + 7 and such a sudden defeat. I would not say that Croatia is in no danger, they still have to play away in Wales, and usually at home Wales plays 100% and if they beat Croatia, they will be equal to Croatia on points.
In any case, Croatia have a good chance to qualify due to their matches against Armenia and Latvia, but now Croatia have made it harder for themselves to qualify. If Croatia wins, they would seem to be out of the group ahead of schedule.
They don't need to worry about Latvia (1 win from 6 matches). Also, Armenia is out of form due to all those political issues related to Nagorno Karabakh. And Wales is down ever since Gareth Bale retired. So as such, there is no direct threat to Croatia and they should be able to qualify without much issues. The only question is whether they can top the group or not. That is still possible since Turkey has played one more match compared to them. This was supposed to be a very competitive group. But as things stand, Turkey and Croatia should qualify with ease.