Create a futuristic mecha fighter designed with sleek, modular plastic armor that features vibrant colors and a gradient effect. The mecha is standing in a dynamic pose, holding a luminous sword with a glowing energy core, emitting beams of light. The background should depict a neon-lit cityscape, showcasing tall skyscrapers and flying drones. The armor should have LED accents that pulse with light, and the overall design should emphasize agility and advanced technology