高冷学长清新学姐
[gāo lĕng xué zhăng qīng xīn xué jiĕ]
This juxtaposes aloofness ('gao leng', literally high and cold) of senior male students with freshness or vitality ('qīng xīn') associated often with female juniors or seniors. It describes personalities contrasting within school dynamics: distant vs. approachable.