It's the first thing people see and the last one on many home, the color of the front door. ''People are starting to branch out'', says Amy Wax, an architectural color consultant. ''They realize the color of the front door introduces the world to the people inside, and it can be unexpected and playful''. before you dash off for a quart of neon green, however, Wax recommends stepping back and taking note of the style of the door, along with the trim and siding that frame it. Adding a stately shade can make a simple cottage-style door look more sophisticated, she points out, while a casual, bright hue can make a formal facade friendlier and more whimsical ....