Any interior decorator will tell you, there’s a fine line between blush and bashful. Unfortunately for Aio Wireless, the same can’t be said of plum and magenta, at least not in a court of law. T-Mobile announced today that a Federal Court in Texas has ordered the AT&T subsidiary to stop using a “plum color as a central part of its trade dress,” as it is “confusingly similar” to its own trademark magenta.

A federal court has granted T-Mobile a preliminary injunction against AT&T subsidiary Aio Wireless on grounds that the low-cost carrier’s color scheme infringes on T-Mobile’s iconic magenta. In the decision, Federal District Court judge Lee Rosenthal writes that “T-Mobile has shown a likelihood that potential customers will be confused into thinking that Aio is affiliated or associated with T-Mobile based on the confused association between Aio’s use of its plum color and T-Mobile’s similar use of its similar magenta color.” The opinion preliminarily prohibits Aio Wireless from using its plum color in advertising, marketing, and store design.