How does BBK x5sl mobile phone set the short message text to white on black background?

It is suggested that you can change the background of information conversation and the dialog bubble box to use it. The setting path is: click information to enter-click the menu button in the lower left corner-Set-Set in the dialogue bubble box (you can change my bubble box and another bubble box), and change the dialogue background in the dialogue background (you can use the pictures in the photo album to set it).