I installed Kubuntu on top of my existing Ubuntu 12.04 (64 bit) installation. During Kubuntu installation, I chose lightdm as my default display manager (instead of kdm). Now after rebooting, the Grub has a new color (gray instead of default purplish) and the screen while booting is gray (instead of purplish). I am curious if it is possible to change this grub behavior without removing Kubuntu. I did find a lot of discussion about modifying grub themes but they were not very useful because I do not know what is the default unity grub theme. I did reinstall grub but it didn't change anything. I tried the Grub Customizer but couldn't succeed. Thanks in advance!