SAN FRANCISCO — Goodbye, Apple Genius Bar. You are being replaced by a tree-filled Genius Grove, which will have more room to sit and more Apple customer service specialists to troubleshoot devices.

On Thursday, the 15th anniversary of the first Apple retail store, the technology company unveiled what it called its largest product: a new design for its sales outlets.

Apple’s 477 physical stores are showrooms for the Apple lifestyle, not just places to buy the latest iPhones, iPads, Macs and accessories. As the company tries to reverse a recent slump in sales, luring newcomers to the Apple brand and persuading existing customers to buy more Apple goods and services have become more important than ever.

The first store with the new look — a two-story location in San Francisco’s Union Square that will open to the public on Saturday — has 42-foot-tall glass doors that slide open to expose the interior to the street.