The main door of a house serves as both a functional entry point and a significant design element. It typically reflects the overall style of the home and sets the tone for its aesthetic. Common features indoor design include:

Material: Doors can be made from various materials such as wood, metal, fiberglass, or a combination. The choice often depends on the desired aesthetic, durability, and maintenance preferences.

Style: Doors come in a range of styles, from traditional to modern. Common styles include panel doors, glass-paneled doors, French doors, and contemporary designs.

Color: The color of the main door is crucial in enhancing the overall curb appeal. It may complement or contrast with the exterior of the house.

Hardware: The choice of doorknob, handle, hinges, and other hardware elements adds to the door's functionality and contributes to the overall design.

Glass Elements: Many doors incorporate glass elements for aesthetics and to allow natural light into the entryway. This can range from small decorative windows to full glass panels.

Architectural Details: Some doors feature architectural details such as carvings, molding, or raised panels, adding a decorative touch.

Security Features: Depending on the location and homeowner's preferences, the main door may include security features such as a peephole, a sturdy lock system, or smart lock technology. 

Weather Resistance: Consideration is given to the door's ability to withstand weather conditions, including rain, wind, and sunlight, to ensure durability over time.

Overall, the main door design is a blend of functionality, security, and aesthetics, contributing significantly to the character of the home.