On a desktop/laptop/netbook you do not want loads of bright colours and ‘jazzy’ presentation, a simple GUI is more than good enough for that platform. It may be different for users of microscreened ‘smart’ phones as their miniscule display needs all the help it can get just to see anything.
So maybe the ‘mobile’ version of Avast might need the over-bright colours but desktop users do not need nor want that. Sensibly gentle colours that do not ‘grab’ the eye are want they want and need I suggest. Simple ergonomics should be applied.