I tend to prefer earthy colors in autumn and winter, so the blue roll neck is uncharacteristic for me at this time of the year.

Is this outfit office appropriate as smart casual or too casual?

Yes. I know the jeans are too tight in the current part of the fashion cycle. I am okay with that.

Coloniaire Suede overshirt
Gran Sasso roll neck
Levi's 502 jeans
Myrqvist Chelsea boots