As quarter-life crises go, the one experienced by tousle-haired musician Nicolau in “The Luminous Life” looks more endurable than most. Yes, he’s unemployed, living at home, recently broke up with his dream woman and is firmly convinced that he’ll never love that way again — but it’s spring in Lisbon, the city’s sidewalks, bars and cinemas are alive with social possibilities for an affable, handsome young lad such as he, and he’s not about to miss out on all of them. Which is to say the title of Portuguese director João Rosas‘ debut feature isn’t at all ironic: This droll, delightful romantic comedy is an ode to the good times that can be had amid and around heartache, and the healing that eventually comes out of that very conflict.

To most viewers, Nicolau — played with irresistible, lightly goofy guilelessness by Francisco Melo — will be a welcome new acquaintance. But for Rosas, and anyone who’s followed his career to date, the character is a familiar one, developed across 12 years and three short films along a coming-of-age arc roughly akin to François Truffaut’s Antoine Doinel. In the last of them, 2020’s “Catavento,” the teenaged Nicolau was on the awkward brink of adulthood; in the first full-length outing for director, character and actor alike, the boy has become a man, only to realize what a boy he still is.

Not that audiences require any of this background knowledge to enjoy “The Luminous Life,” which is fully self-contained and broadly, wittily relatable in its depiction of Zoomer liberties and insecurities. Bowing internationally in Karlovy Vary’s main competition — having world-premiered on home turf at IndieLisboa — Rosas’ film has the makings, given the right multi-platform arthouse handling, of a generational touchstone for curious younger cinephiles. At the very least, further festival programmers will jump on a sunny, easygoing item that will serve as a bright palate-cleanser in any program dominated by heavier fare.

It’s been going on a year since Nicolau was dumped by long-term girlfriend Inês (Margarida Dias), a woman who, to hear him describe her, represents such an unmatchable apex of femininity that he may as well live the rest of his life as a eunuch. Still, it’s his 24th birthday, and his friends won’t let him mope the day away. Instead, they rope him into watching a choral performance that opens the film on an ebullient, life-giving note, before going on to less dignified, more drunken hijinks. Joining in the festivities is outgoing French student Chloé (Cécile Matignon, hugely appealing), ostensibly in a relationship but flirting brazenly with Nicolau, who even after a few beers is too mournful to pick up the signals. While his longtime best friend Mariana (Francisca Alarcão, also a recurring presence from the shorts) encourages him to get laid — “She doesn’t have to be the love of your life” — he sees no value in casual pleasure.

And yet life keeps handing it to him anyway, in fits and starts that eventually add up to a complete renewal: an apartment share away from his parents, who are going through life changes of their own; a new job with friendly colleagues at the city’s cinemathèque; a breakthrough gig for his long-languishing band; even the possibility of a relationship if he’s willing and eager enough to chase it. In part, “The Luminous Life” is a lesson in embracing the new, while elsewhere, it cautions us to revisit past chances and encounters we may have passed up too hastily.

Either way, it’s a buoyant celebration of saying yes rather than no, and a valentine to a vibrant, spontaneous city where no man can remain an island for too long. Rosas and cinematographer Paulo Menezes shoot Lisbon’s streetlife, nightlife and even its quiet cemetery parks with the breezy, sauntering flow of Eric Rohmer’s Paris, and occasionally the hot-to-the-touch luminescence of Wong Kar-wai’s Hong Kong. Café lamps flush rosily along with the characters’ faces. A white Breton-striped tee ripples and positively gleams in outdoor morning sunlight. “The Luminous Life” is a film built from such small, fleetingly feelgood sensory details — moments that can brighten a day or, if enough of them line up just right, get a broken heart restarted.