Explain Flutter architecture and its components.

Flutter architecture layers:\n\n**Framework Layer (Dart):**\n• Material/Cupertino - Design systems\n• Widgets - UI components\n• Rendering - Layout and painting\n• Animation & Gestures - User interactions\n\n**Engine Layer (C++):**\n• Skia - 2D graphics rendering\n• Dart Runtime - VM and isolates\n• Text - Text layout and rendering\n• Platform Channels - Native communication\n\n**Embedder Layer:**\n• Platform-specific code\n• Android (Java/Kotlin)\n• iOS (Objective-C/Swift)\n• Desktop (C++)\n• Web (JavaScript)\n\n**Key Components:**\n• **Widget Tree** - Immutable UI description\n• **Element Tree** - Widget instances\n• **RenderObject Tree** - Layout and painting\n• **Layer Tree** - Compositing\n\n**Benefits:**\n• Consistent UI across platforms\n• High performance rendering\n• Hot reload for fast development\n• Single codebase maintenance