He gives a faintly bemused little smile in return, spanner twisting in his hands as he pauses in the act of tightening a bolt. It's strange to see her grinning at him like that. Nice, but strange. "About a month," he replies. Just long enough to satisfy the demands of pride - what, like he was going to admit it'd been a terrible decision - before he surreptitiously acquired some actual dye to return his hair to something approaching its natural color.