Mobile Fitness App UI

Mobile app UI design for a {app_type: premium personal training and fitness app}.

Visuals:
- {screen: "Activity Overview" featuring a large calorie ring and step counter}
- {palette: High-contrast (Vibrant Orange, Deep Black, and White)}
- {graphics: High-quality photo of a runner in the background with a gradient overlay}
- {buttons: Rounded "Start Workout" button with a subtle shadow and glow}

Composition:
- {elements: Bottom tab bar with icons (Home, Workouts, Progress, Profile)}
- {card: Horizontal scroll of "Available Classes" with time and difficulty tags}
- {mood: Energetic, motivating, athletic, clean}

Technical:
- {resolution: 4k high-fidelity mobile render}
- {device: Shown in a modern bezel-less smartphone frame}

Style: {aesthetic: Dynamic, sporty, modern, high-energy}