Describe the impact of Frank Miller's 'The Dark Knight Returns' on Batman's art style.

Frank Miller's 'The Dark Knight Returns' (mid-1980s) was a watershed moment, ushering in a more mature, deconstructive, and often brutal art style for Batman. Miller's work featured heavy inks, jagged lines, distorted perspectives, and a raw, expressionistic quality. This style emphasized the psychological wear and tear on Batman, portraying him as a grizzled, aging vigilante. It heavily influenced the 'grim and gritty' aesthetic that dominated the late 80s and 90s.