Apex domains cannot have CNAME records.
Question and response
Question
dig styria-it.hr. NS
Answer
styria-it.hr. 5 NS dns1.styria-it.hr.
styria-it.hr. 5 NS dns2.styria-it.hr.
Authority
The response has no authority records.
Additional
dns1.styria-it.hr. 5 A 193.25.220.95
dns2.styria-it.hr. 5 A 193.25.220.94
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0