You may have to be a bit of a color theory junkie to appreciate this one. It is pretty close to a complimentary discord. The complimentary part of that phrase points out that the yellow green and reddish purple are at opposite sides of the color wheel. And discord points out that the value (ie the lightness or darkness of a color) of the purple has been lightened to a similar value as the yellow. What that all boils down to is it causes a thing in your eye called reticulation. A vibration of sorts.
I'm bet this is too much information. I probably shouldn't even go into the contrast between the transparency of the background versus the opacity of the lattice. So I'll just cut this short, and say Hey! Look at this, it's pretty cool!