style

>>2867768
It can be done in a variety of digital programs such as photoshop. It's just some simple shapes that have had some paper textures applied to them.

looks like watercolors

Digital art
Sketch to establish composition
Background of white
New Layer
Textured brush all over
Lock transparency and use dark blue at low opacity to adjust the color of sections of the wall
New Layer
Shift+click to get straight lines, draw windows
Paint shadows in layers with dark blue. One layer = light blue, two = medium, three = dark
Rotate canvas to angle
Erase out shine of glass
Paint in opaque details in blue and white, using Shift+Draw whenever necessary for straight lines
Done