What are the characteristics, principles, values, and themes of Romanticism in "Young Goodman Brown"?

Certainly, Hawthorne's "Young Goodman Brown" is infused with the Puritan values of seventeenth-century America. However, the story also incorporates many elements of Dark Romanticism. As a movement, Dark Romanticism was popularized during the early nineteenth-century, rather than the seventeenth. Hawthorne, however, wrote "Young Goodman Brown" in 1835, and he saw fit to include elements of Dark Romanticism in the story. Perhaps he saw it as a good way to highlight some very important themes.
First, let's discuss the Puritan values in the story. In seventeenth-century New England, Puritans made a clean break from the Church of England. The group of believers maintained that secession was necessary because King Henry VIII's new church had failed to reject all Roman Catholic traditions. For the most part, the Puritans thrived in New England, but their communities soon became embroiled in controversy. First, Puritans were inherent "literalists." In fact, antinomians (those who reputedly rejected the Mosaic or Old Testament laws) often clashed with the Puritans, who insisted on the idea of Original Sin. The Puritans also believed in predestination, the idea that God had chosen some for salvation and others for condemnation (in hell).
We can see the themes of Original Sin (or the intrinsic depravity of all humanity) and predestination in "Young Goodman Brown." However, Hawthorne wraps these two themes in the embrace of Dark Romanticism and invites his readers to ponder a horrifying possibility: what if "predestined" saints were really Devil-inspired sinners in disguise? This possibility, of course, reinforces the theme of Original Sin but turns the idea of predestination on its head.
Hawthorne skillfully uses Dark Romanticism to emphasize the Puritan obsession with sin and the innate fear of the Devil as the progenitor of all evil. For its part, Dark Romanticism was a fusion of Romantic and gothic elements. We know that gothic stories mainly focus on death, sin, blood, horror, and decay. For its part, Dark Romanticism readily portrays human beings as sin-sick, depraved souls. Also, goblins, ghosts, frightful apparitions, and demonic creatures often figure prominently in such stories.
We see this preoccupation with the gothic in "Young Goodman Brown."

The whole forest was peopled with frightful sounds; the creaking of the trees, the howling of wild beasts...
Either the sudden gleams of light, flashing over the obscure field, bedazzled Goodman Brown, or he recognized a score of the church-members of Salem village, famous for their especial sanctity. Good old Deacon Gookin had arrived, and waited at the skirts of that venerable saint, his reverend pastor. But, irreverently consorting with these grave, reputable, and pious people, these elders of the church, these chaste dames and dewy virgins, there were men of dissolute lives and women of spotted fame, wretches given over to all mean and filthy vice, and suspected even of horrid crimes. It was strange to see, that the good shrank not from the wicked, nor were the sinners abashed by the saints.
...there could be nothing more frightful than the figure of Goodman Brown. On he flew, among the black pines, brandishing his staff with frenzied gestures, now giving vent to an inspiration of horrid blasphemy, and now shouting forth such laughter, as set all the echoes of the forest laughing like demons around him.

Our protagonist loses his faith altogether when he sees the hellish scene before him, where every esteemed individual in his congregation is a Devil-worshiper. Indeed, the wicked are engaged in close fellowship with the "good," which turns on its head the Puritan belief in predestination. Additionally, in Dark Romantic works, nature is often portrayed as a malevolent force that is imbued with menace. It is therefore interesting that Goodman Brown learns the true secrets of his congregation in the deep, dark forest.
For more on Dark Romanticism, please refer to the link below.
https://www.newworldencyclopedia.org/entry/Dark_romanticism