heh. so long as you maintain a roughly gray scheme, it won't make such spaces all that visible. even the below examples jump quite a bit in color, yet most of them are hardly noticeable.
[color=0e0c0c]a[/color]
[color=202121]a[/color]
[color=222323]a[/color]
[color=242525]a[/color]
[color=262727]a[/color]
[color=282929]a[/color]
[color=2a2b2b]a[/color]
[color=2c2d2d]a[/color]
[color=2e2c2c]a[/color]
[color=3e3c3c]a[/color]
[color=5e5c5c]a[/color]
[color=7e7c7c]a[/color]
[color=9e9c9c]a[/color]