車輪の国、向日葵の少女 OP FullSharin no Kuni, Himawari no Shoujo
曲名: 紅空恋歌Akazora Renka
歌手: 片霧烈火Katakiri Rekka
作曲: 片霧烈火 (Katakiri Rekka)
Sharin no Kuni, Himawari no Shoujo OP Full with English lyrics/subtitles

あかぞられんか良いよね…　特に歌詞が格好良くて大好きです

P.S: 1:17 It is the cheek that is dyed in scarlet, not the tears (which actually makes sense since it's sunset). Thank god she's not crying tears of blood!
The lyrics are pretty cool imo. They really match with Katakirisan's voice (at least when she's not singing something like girl meets love, lol).