Graceful Degradation vs Progressive Enhancement

Both PE and Graceful Degradation (GD) deal with the same problem: different browsers and environments support different features. PE builds up from a baseline; GD strips down from the cutting edge. The choice shapes the entire architecture.

PE starts with the lowest-common-denominator HTML that works everywhere, then adds layers (CSS, JS, advanced features) that enhance the experience on more capable browsers. The baseline experience is the reference point.