DSD had Barbie pink walls that we nullified with large stamped white daisies along with lilac skirting boards.
Hideous, and completely anti the blue/red/white Nordic chic we forced on DD1, but you know what? She remembers it and loves it, even now, at 18.
Bite the bullet hard, and give her the garish marshmallow paradise she craves - but make sure she's got plenty of connex and meccano too