Meaning of 道一声晚安， 许一弧月色

Question

Does '道一声晚安，许一弧月色' mean goodnight? Is it something like an idiom, where it comes from and is it used often?

Answer 1

I think is basically an expression of care and concern.

"道一声晚安，许一弧月色"
(I will) say Good Night, may the moonlight accompany you.

The deeper meaning?
(I believe 简书jiǎnshū refers here to an App for reading short stories.)

这句话的意思是每天晚上有人对你说晚安，
The meaning of this phrase is, every night there are people who wish you Good Night,
就像得到月光的庇护一样开心。
which is like the happiness you get from being under the moonlight.
人的一生中都需要得到别人的问候和关爱，
In our lives we all need to receive other people's greetings and concern,
如果有一个一直关心的你的人，
If there is always someone who shows concern for you,
那该是多么幸福的事情呀。
what a happy circumstance that is!
所有的事情都在发生。
Anything can happen.
所有的痛苦永远不会磨灭。
No bitterness can erase (such caring concern).
我们只能保持平常心。
We can only remain steadfast.
简书里面的原句是我喜欢的少年，
The original sentence is from a reading App called Jian Shu, which I liked in my youth,
道一声晚安，许一弧月色。

Answer 2

Found this on the web: “道一聲晚安，許一弧月色”“長夜漫，獨願汝安”

Seems like words on a well-wishing card

道一聲晚安 - Say words of goodnight

許一弧月色 - promise you a crescent moon's light (promise to spend a night with you under a crescent moon - a romantic notion)

長夜漫，獨願汝安 - night is long, just wish you safe (or at peace)