A black knit turtleneck and pants that are essentially glorified leggings are perfect for hiding that cookie or two that you didn't really need and an ivory ruffle wrap is a cozy way to stay warm. Try layering the wrap over your coat when you're outside to avoid uncomfortable bulkiness. A rhinestone necklace adds a bit of glamour and pops of red in the shoes and makeup are a nod to the Christmas spirit.
Another one of my favorite casual Christmas looks this season is a fair isle sweater layered over a chambray shirt or a vintage inspired Christmas shirt, a classier take on the tacky Christmas sweater. Of course, anytime I'm doing Christmas casual around the house, you're going to find me in a pair of pajamas.