[Could someone explain the colours?]

Thanks for the help, I had used the lay flat option but that didn't Eem to make any difference. To fix it I rotated the model in the shapr software so that Cura didn't have to rotate it and it got rid of the dark blue. 

[Could someone explain the colours?]

Hi

It's probably something quite simple but could someone possibly explain something I've noticed? I've taken a screenshot of a model I'm printing, if you look at it from below most of it is showing as light blue which I presume means its touching the bed, a few bits of red where it needs support. The bit I don't understand is the dark blue section, can anyone help?

 

Thanks