Five Finger Death Punch - Brighter Side of Grey (Official Audio)⁠⁠

Im writing this in case I'm gone tomorrow

I'm writing this in case I've moved along

There's something that I hope you'll remember

That life is not a game, it's a song

So take the best parts of me

Locked away without the keys

And know that I'm forever by your side

When the lights go down

Know that I am never far away

When the sun burns out

I'll be waiting on the brighter side of grey

If you're reading this, I know you're feeling sorrow

If you're hearing this, I know you're probably scared

Just know that all the things you want are borrowed

And all you get to keep is all you've shared

So wipe away the tears for me

Know that we've made history

Remember no one ever really dies

When the lights go down

Know that I am never far away

When the sun burns out

I'll be waiting on the brighter side of grey

[Instrumental Break]

When the lights go down

Know that I am never far away

When the sun burns out

I'll be waiting on the brighter side of grey

Как понять  -  brighter side of grey, я не совсем понял. Это идиома какая то?