Current idiom 'In the pink' refers to being in the best possible health. Glowing pink cheeks, a blushing bride, a beautiful baby.
'In the Pink' during the 16th century meant - the pinnacle of something but not limited to health.
Shakespeare's Romeo & Juliet, 1597:
Mercurio: "Why, I am the very pinke of curtesie"
Mercurio means that he is not just courteous, but the very model of courtesy.
This citation is from Leigh's Kensington Gardens, 1720:
"Tis the pink of the mode, to marry at first sight: And some, indeed, marry without any sight at all."
Charles Dickens, in his 'Letters 1845', demonstrates a significant difference to our current usage:
"Of all the picturesque abominations in the world, commend me to Fondi. It is the very pink of hideousness and squalid misery".
From my perception, Fondi is a delightful, pretty resort, surrounded by mountains on the Lazio coast lying midway between Rome and Naples.
What is pink? a rose is pink
By a fountain's brink