Those large single pane windows are perfect for that waterfront view. Classical architecture is always beautiful; but must be watered down a bit sometimes to get important features like ‘mullion-less’ windows.
I think some historical districts mandate the multi-pane windows with the grid of mullions around each small pane of glass; it is an ‘authentic’ traditional look - but results in a significant loss in views out the windows.
Yes, those dark mullions would look awful on the inside. Those frames are all made of extruded aluminum, with a power coat (baked on) paint finish. That white color helps keep the interior looking light and airy…
Here is an example - not necessarily the same brand, but same ‘type’…
I don’t think I would want dark window frames on the inside unless I was doing a room with dark paneling. My library has deep wine painted walls with medium stained cherry book cases and yet the white windows look fine. Of course I live in Southern California so kind of Florida. lol
This one is almost done. The construction scaffolding and sidewalk barriers have been removed. I particularly like the look of the entrance door detail, along with the bay windows above; the stone, the steel with rivets, the intricate decorative stone & metalwork surrounding the door - all artfully designed.