At an uptown amphitheater, the Classical Theater of Harlem stages Shakespeare’s comedy with fizzy delight.For so many of us, stress roared in and put down roots. The stress of living at perpetual high alert in a world that has seemed, for the past several years, to be in an ever-shifting state of emergency. Amid all that, in the post-shutdown theater, has come a tsunami of shows dedicated to elucidating social ills and processing cultural pain. Such work is vital now and always; don’t get me wrong.But we desperately require its counterweight, too — shows that usher us into alternate worlds where we can give ourselves over to pure delight. The Classical Theater of Harlem gets that, deeply, and proves it with a delectable “Twelfth Night” so fizzy and fun that you may be surprised afterward at how relaxed your body is, and how much lighter your spirit feels.That’s what communal joy can do. Maybe it’s been a while?Hie thee, then, to the Richard Rodgers Amphitheater in Marcus Garvey Park, where this free, outdoor production directed by Carl Cofield boasts dance as lissome as ever, design that raises the bar on this company’s customary visual wow and a cast whose ease brings a lovely clarity. In Kara Young as Viola, this “Twelfth Night” also has a star as fascinatingly natural in Shakespeare as she has been in any of the contemporary stage roles that have established her as one of New York’s most exciting actors.Washed up on the shore of Illyria, her Viola is immediately surprising — shivery and traumatized, which makes the unseen shipwreck that tore her from her brother, Sebastian, more than a mere plot device to set in motion a rom-com with a mistaken-identity twist. Not that she lingers in her distress; this show gets playful fast. But the emotional stakes are laid, and they will pay off.Needing to survive in this strange country, Viola disguises herself as a young man named Cesario and gets a job working for Orsino (William DeMeritt), a love-struck duke who sends her to plead his amorous case with the countess Olivia (Christina Sajous). The elegant lady spurns Orsino’s messages but is much taken with the messenger, who, in turn, is so smitten with the oblivious duke that she can barely stand to be near him. It’s a triangle of sexual tension, one of romantic comedy’s most deliciously tormented shapes.An intersecting plot involves Shakespeare’s possibly most stellar team of ridiculous idiots: the ever-reveling Sir Toby Belch (Chivas Michael) and his tag-along friend Sir Andrew Aguecheek (an excellently goofy Carson Elrod), who with their raucous compadres stir up trouble for trouble’s sake at Olivia’s house. Their principal target is Olivia’s prim steward, Malvolio (Allen Gilmore), who, despite his name, is not a bad guy, really; he’d just like to get some sleep instead of being kept awake by these cases of arrested development.This beautiful show, at the Richard Rodgers Amphitheater, works its magic beneath the summer sky as dusk turns to dark.Richard TermineCofield and his creative team are gorgeously in sync as they fully embrace all comic opportunities — not least a memorably silly sword fight between Viola and Andrew, both of them terrified and armed with quasi-light sabers. (Fight direction is by the father-and-son team Rick Sordelet and Christian Kelly-Sordelet.) There is also the laugh-out-loud tableau of Toby, Andrew and the servant Fabian (Donathan Walters) popping their hatted heads up from their hiding place to watch Malvolio fall into their trap. (Set design is by Riw Rakkulchon, costumes by Mika Eubanks and lighting by Alan C. Edwards.)What befalls Malvolio is the one indelible blot on Shakespeare’s play: recreational cruelty that can’t be jollied away. In this production, though, the rest is lively, witty, fresh — and peppered with crowd-pleasing songs performed by Olivia’s scooter-riding jester, Feste (Israel Erron Ford) — in one instance, with Toby and Andrew as backup dancers. (The original music is by Frederick Kennedy, who also did the sound design; choreography is by company regular Tiffany Rea-Fisher.)As with any oft-told tale, the enjoyment of “Twelfth Night” lies not so much in the destination as in the journey. We know that Sebastian (J’Laney Allen) will turn up, that people will confuse him and Viola — the show’s hair designer, Earon Nealey, is instrumental in this illusion — and that it will all end happily with the romantic triangle squared.This is one of those productions that make you feel lucky to be in New York. You have not seen a Viola like Young’s fierce, funny, fully inhabited Viola. And if your nerves are as frayed as so many of ours are, you could do with the beautiful balm that is this show, working its magic beneath the summer sky as dusk turns to dark.Twelfth NightThrough July 29 at the Richard Rodgers Ampitheater at Marcus Garvey Park, Manhattan; cthnyc.org. Running time: 1 hour 30 minutes. More