That's a maritime border. Generally, when people talk about countries bordering each other, they mean land or river borders. If we were including maritime borders, we'd also have to include Montenegro, Albania, Spain, Tunisia, Algeria, Malta, and Greece, not just Croatia.
Make it 15 or 10 seconds.
7 seconds :'l
(I have gone to Switzerland, Liechtenstein, United Kingdom, Ireland, Ukraine, Croatia, Slovenia, Austria, Germany, France, Italy, etc ;-;)
Now I'm being extremely arrogant :'D
https://sovereignlimits.com/wp-content/uploads/sites/2/2019/04/HRV_ITA_web.jpg