<human>:  What is the difference between Roman shades and roller shades?
<bot>: The main difference between Roman shades and roller shades is in their design. Roman shades are a type of window treatment that typically fold and collapse up and down, while roller shades have a roller mechanism that rolls and unrolls the fabric of the shade when being opened or closed. Roman shades generally provide a more sophisticated and stylish look, whereas roller shades tend to be simpler and more practical.