Blazing sunsets, dreamy islands, and Roman ruins lure millions of visitors to Croatia.   Fortunately, this picturesque country lapped by the turquoise Adriatic Sea can still be experienced by luxury travelers with minimal crowds. On a recent trip to Croatia, I discovered the Impresia Collection of Croatia Hotels, a group of luxury hotels scattered across the country that immerse guests in Croatia’s natural wonders, rich culture, and medieval architecture.   Impresia is not a hotel chain. Instead, it’s a prestigious mix of unique accommodations that can...