I believe that these two are meant to be implied as something more but the anime so far is acting like yuri bait. It been showing glimpses of yuri or subtext. Like chapter 4 they caressed their hands on the face and blushed then chapter 7? Kukuru was worried over the closure of gama game and hugs fuuka. Fuuka has been living or sleeping next to kukuru. Then chapter 11 or 12 the typhoon weather happened and fuuka was there supporting her and was her emotional anchor. Then the latest episode 13 she came back and supports her again. The problem is the anime is trying to act like they are a couple there are moments which are Tender or seem loving. But I have a feeling its not the main focus or trying to mask it under the guise of being sisters. I dont know if kukuru will lean into a gay relationship or if the show will end with them just remaining as close sister vibes. So far it does feel bait but I can't be sure. Regardless its not bad anime even if it isn't 100% yuri the vibes are still there to a degree. Least it's not like synphogear where they hinted it and never showed anything. You do get tender moments like hugs or something.