This Is the Happiest Show of Fashion Week

Welcome to Runway Matters, where we're delivering notes straight from the runway so you can quickly digest the most important trends and noteworthy moments from the F/W 18 shows.

Rosie Assoulin is one of those fashion week presentations that editors, myself included, spend all week looking forward to. Not for the snacks (though this year's crêpe station was a definite crowd-pleaser), but for the unending happiness we feel walking into the room. Season after season, the designer manages to weave smile-inciting details into her clothes—a whimsical neckline here, a jangly earring there.

F/W 18 was no exception. Models danced and swayed in marbled suits, spangled dresses, and Rosie's signature pops of color. What connected the designs was not necessarily a cohesive theme, but an effortless energy that seemed to flow from one look to the next. Every seam and button was a bright spark that made it hard to know where to look next.

And, since it's the age of Instagram after all, it should come as no surprise that everyone in the room was snapping detail shots of the collection left and right. Below, find four details to know from the show.

Detail We Loved: Marbled Magic

One theme that continued throughout the collection was a marbled pattern that models wore from head to toe.

The Crowd Favorite: A New Kind of Two-Piece

While a gown may make for traditional eveningwear, this stunning two-piece is proof that there's another way to do black-tie dressing.

Don't Overlook It: The Shoes

We love Rosie's clothes, but this season, her shoes were equally drool-worthy, from delicate mules to funky bucket boots.

The Trend to Try: Power Clashing

There's never a shortage of color at a Rosie show, but this season more than any before confirmed the fact that power-clashing colors are here to stay.