世界は恋に落ちている (Sekai wa Koi ni Ochiteiru)

Background
This song was uploaded to Niconico Douga on February 23, 2015 with two versions, the original one, sung by CHiCO and an official Vocaloid cover, sung by GUMI. CHiCO's version has reached over 1 million views while GUMI's version has reached over 300k views, entering the Hall of Fame.

Sekai wa Koi ni Ochiteiru was used as the opening for the anime.

Trivia

 * The song is also used as the opening theme in the anime television adaptation of the manga series  (アオハライド Aoharaido?, written Ao Haru Ride within Japan).