Monochrome chic. Simple is best in a narrow hallway. White painted stairs make them appear wider and the grey runner is both practical and elegant. Seek out a slim console - vintage or modern - thats useful and decorative but not space-consuming.
We're replacing the curtains with shutters, but this is Farrow & Ball "Pigeon" - I found it so helpful when people put the name of the paints on Pinterest, as it definitely is different to the website.