Maxwell Ryan is a designer and founder of the popular Apartment Therapy blog. (Apartment Therapy Media)

"Apartment Therapy Complete and Happy Home" by Maxwell Ryan and Janel Laban. (Melanie Acevedo)

Maxwell Ryan became an “apartment therapist” in 2001 to help clients in New York shape their spaces into comfortable and personal retreats. As he traveled by scooter to various boroughs, he found many people unhappy with their interior lives and looking for guidance as to how to achieve domestic harmony.

In 2004, he and brother Oliver launched the Apartment Therapy blog, which provides daily inspiration for decorating, DIY projects, renovating, de-cluttering and massaging interior spaces. It’s become an influential online community that is a window into the soul of millennials, many of whom are embracing urban life and its limitations and possibilities.

Ryan, 49, has just published his fourth book, “Apartment Therapy Complete + Happy Home,” which he wrote with Janel Laban, the blog’s executive editor. He is currently on a cross-country road trip in a 1991 VW van promoting the book and dispensing a bit of design advice along the way. The book has photos from 75 rooms, and it details how to find, create and maintain your place.

“Our readers consider the home an emotional space as well as a living space,” Ryan says. “The concept of happiness and a home that makes them happy is what they come back to again and again.”

Ryan says the blog’s main audience is ages 25 to 35. Millennials, he says, are into finding themselves. “There is not one style you are seeing. They are interested in smaller shops and the one-off, the unique, products from Etsy. They are not driven by budget. They will absolutely splurge on something. They use Ikea a lot, but Ikea is a backup and not an aspiration.”

An average of 17 million people click on Apartment Therapy and its sister blog, The Kitchn, each day, according to an Apartment Therapy spokeswoman. The blogs take readers into the entryways, cupboards and nurseries of homes from Topanga Canyon, Calif., to the Bronx, so they can be studied and mined for ideas. Here is a list of five trending design themes Ryan and his team have spotted.

Dark, moody colors

A kitchen from “Apartment Therapy Complete + Happy Home.” (Melanie Acevedo)

Ryan is seeing a deeper color palette in the homes that have recently appeared in his blog. Dark colors add depth and richness to an interior. Deep blue has been very strong for a number of years. Black is big, too, and chalkboard paint is part of this. Other hot hues: rich, dark green (think velvet), charcoal, deep plum and eggplant.

Texture

A sitting area from “Apartment Therapy Complete + Happy Home.” (Melanie Acevedo)

Using lots of textures is a great way to instantly make any room cozier and more interesting. A blog post by Apartment Therapy senior writer Nancy Mitchell mentioned finding a balance using things such as kilim pillows, tapestries, linen bedding, books, Ikea sheepskins, rugs, velvet and antique woods.

Global influence

A globally inspired living room from “Apartment Therapy Complete + Happy Home.” (Melanie Acevedo)

Textiles and treasures from all over the world add interest and vibrancy to a home. A recent blog post featured a house that mixed white walls and neutral furnishings with colorful textiles, handmade accents and far-flung collections.

Plants

Plants are turning up in abundance, as in this room from ”Apartment Therapy Complete + Happy Home.” (Melanie Acevedo)

The ’70s favorite is back. According to a recent blog post by Mitchell: “Houseplants are experiencing a huge surge in popularity right now. You see them everywhere, and sometimes you see a whole lot of them, in delightful clusters.”

Mixing old and new

An old fireplace sets off a modern chair from “Apartment Therapy Complete and Happy Home.” (Melanie Acevedo)

Matchy-matchy furniture is out. Mixing old and new gives a room a sort of thrift-store-chic look — the opposite of buying a whole set of furniture in one store. A recent post on mixing traditional pieces with modern gave this advice: Hit the flea market and Grandma’s attic.