Ganbare, Douki-chan

Douki-chan is a respectable office worker with one goal: to seduce her coworker Douki-kun. Unfortunately, this proves to be easier said than done, as her plans are constantly thwarted by Kouhai-chan and Senpai-san—her two love rivals who will stop at nothing to gain the affection of their beloved colleague first. Douki-chan will need all the luck she can get to surpass her competition and win Douki-kun's heart.

(Source: MAL Rewrite)