There's a pretty compelling case that the writers deliberately chose those colors of their clothes.

Reddit comments:

http://reddit.com/r/betterCallSaul/comments/2zczl6/color_theory_fire_and_ice_the_kettlemans/

"When this "Fire and Ice" color theory was first suggested, a lot of the comments cried "over-analysis", but I think the evidence is pretty compelling.

In that first scene where they're wearing blue, when Mrs. Kettleman sticks her hand up to stop Mr. Kettleman from signing the contract, she reveals a red bracelet. It fills up the frame.

You can cry "over-analysis" all you want but it seems pretty air tight to me. Lord knows ol' Vincey-boy loves color symbolism."

He does love color symbolism!

So is the point that they start cool and become devilish?

Check out the red bracelet:

http://pandawhale.com/post/58120/better-call-saul-signature-denied-heart-breaking-gif