I think you could get a bit more expressive with the color choices. you've made a slightly darker + cooler shadow, but didn't vary the hue in that shadow very much, you could add some bits of different cool hues in there for more interest. as long as they're all leaning in the grays, it should still work no matter what color. minimal can still be interesting to look at
your blue background and the white paper would reflect their colors into the orange, and the orange would reflect some, well, orange onto the paper and in the shadows. the blue being reflected into the orange would make some nice compliments too.