I reallllllly don't mean to look to far into things unnecessarily, buuuuuuutttttt some things have been shown to mean a helluva lot more than they seem at first glance. If Shou takes time to give any amount of proper respect toward even a minute detail, it has been proven to very frequently mean something far greater.
Now direct our attention to the kind of flowers Keiko got...I won't go through and describe them because, well, you can go back and read for yourself. I can find them as a microcosmic symbol for any sort of romantic relationship between the two. Which can be good, bad, or both:
-The flowers are meant to be preserved for a long time, which means Keiko wants their relationship to continue 'blooming' for a long time.
-However there "Is no need to water them"...this might be a language idiom barrier, but that could suggest that maybe Keiko is warning against developing the relationship any further; or it could mean that since the flowers are already going strong and at their peak, there isn't a need to bother putting much effort since the relationship is already at its best point.
-The first doesn't particularly make sense in the case of 'not bringing it into the sunlight'.
Add onto the fact that this is Ran's birthday, Keiko was very excited-nervous to give it to Ran, and the way we purposely didn't get Ran's immediate reaction to anything substantial from Ran (which Shou almost always gives us), I would use to suggest that maybe Keiko is alluding to either the fact they share mutual feelings for each other (perhaps she herself is not aware of the fact?), or maybe their relationship as friends is just really important to her. Or maybe the theory we joked about in passing a few months ago about them having already been in a romantic relationship for a while is actually true.
Or maybe I'm dissecting why the curtain was colored blue when Shou is like "It's because I decided to make it fucking blue".
