Create a vibrant and playful birthday card design, using a clean vector style with flat shapes and crisp lines. The scene is set in a futuristic cityscape, reminiscent of the world of "Divergent" with Theo James' likeness subtly integrated into the scene.

**Foreground:**

1. **Birthday Cake:** Place a towering, futuristic birthday cake in the lower-left corner. The cake should have three layers with angular, geometric patterns and digital-like textures in shades of metallic silver, deep navy blue, and rich gold. A small banner with "Serena" in sleek, modern lettering is wrapped around the top layer.

2. **Theo James Figure:** In the center-right foreground, depict a stylized, abstract representation of Theo James. Use simple, angular lines to suggest his signature look—tousled hair, sharp jawline, and a confident posture. His outfit is a minimalist suit in shades of charcoal gray with subtle blue accents.

**Background:**

1. **Cityscape:** Extend a skyline of futuristic skyscrapers in the background. Utilize sharp, angular designs with variations in height. Color the buildings in gradients of midnight blue, deep teal, and subtle silver accents, giving them a metallic sheen.

2. **Sky Elements:** In the upper portion, illustrate a dynamic, abstract sunburst design. Use concentric circles in vibrant yellows and oranges, with radial lines emanating outward. This should convey an impression of energy and celebration.

3. **Decorative Details:** Add a few floating geometric balloons in the sky, with flat colors of bright red, electric blue, and vivid yellow. These should have sharp, clean outlines and be interspersed amongst the sunburst.

**Color Palette:**

- **Primary Colors:** Midnight Blue, Charcoal Gray, Deep Navy Blue

- **Accent Colors:** Metallic Silver, Rich Gold, Electric Blue, Bright Red, Vivid Yellow

The design should be flat and crisp, using solid colors without gradients, except where specified, to maintain a modern, clean look reminiscent of the artists and movements mentioned.

Generated with these themes: Divergent Theo james.

Made with ❤️ by AI.