I have a theory I've been thinking about. I really like looking for different color symbolism types in media. I find one of the most permeating types in japanese media is the use of red and blue to represent duality and something not appearing as it is. Although I don't see it mentioned often I noticed this a lot when watching Lain but couldn't exactly pin point what exactly it meant. The most obvious one was the mottled shadows in the material world occasionally changing between blue and red as lain did different things. Another was the use of red on all of the non modified navi systems and blue as the major color in all the software.
I could be wrong as I haven't rewatched this show with this specific theory in mind but my guess is that the red represents the material world as blue represents the wired crossing over. As the series progresses these colors seem less prominent possibly showing the two crossing over. This also makes sense considering the red laser motivs of the men in black while the knights use a blue logo.
Arisu is always seen wearing red which would also makes sense considering she's the only thing rooting Lain in the real world. Eiri is always shown wearing blue with the exception of the paint on his eyes which could represent his omnipresence in the material world while still only residing in the wired.
I may just be projecting nonsense here but does this seem noticeable to anyone else?