Black unresponsive screen with Blue LED, Galaxy S6

[AC Question]

Phone working fine all day, haven't updated or installed anything. The screen is just now black and unresponsive, blue LED steady on but fading between light and dark blue. Red light comes on when charging but still no response from the screen. Tried every button combination to try and reboot it but the only change is the led going off and then returning to the changing blue. Any help or advice would be great