Portrait of Zeus, god of thunder, holding a lightning staff, showcasing his muscular build, rendered in a fantasy setting with intricate and elegant details. The digital painting should have a smooth finish and sharp focus, influenced by the art styles of Gaston Bussiere and Alphonse Mucha. The setting captures a sense of grandeur and divine presence, with elements of concept art and illustration. Avoid any visual distractions such as distortions, artifacts, or unnatural proportions, ensuring a cohesive and polished representation of Greek mythology.