A poetic word for "twilight," or the time of day immediately after the sun sets, is gloaming. The best thing about summer evenings is looking for twinkling fireflies in the gloaming.
That romantic time of day when the light has mostly faded but it's not quite dark yet? You can call that the gloaming. This is a word with a strong Scottish heritage, adopted from Scottish dialect during the Middle Ages and rooted in the Old English word for "twilight," glōm. It fell out of use In English for many years, while Scots speakers continued to use it, and was re-adopted in the 1800s.