UI Reasoning: Social Media App. Recommended Pattern: Feature-Rich Showcase. Style Priority: Vibrant & Block-based + Motion-Driven. Color Mood: Vibrant + Engagement colors. Typography Mood: Modern + Bold typography. Key Effects: Large scroll animations + Icon animations. Decision Rules: {"if_engagement_metric": "add-motion", "if_content_focused": "minimize-chrome"}. Anti-Patterns: Heavy skeuomorphism + Accessibility ignored. Severity: MEDIUM.