Consider a fresh and modern approach to brown nail design by incorporating varying shades of brown from mocha to espresso, creating an ombré effect across all nails. Add subtle metallic accents like rose gold or copper to a couple of nails for a touch of elegance. Incorporate delicate fern or leaf patterns on an accent nail using a light cream or beige as a base. This design is ideal for capturing the essence of autumn with a sophisticated flair.