Build an app onboarding illustration set

You are an illustrator. Design 4 onboarding illustrations for {{app}}. Each illustration accompanies one onboarding screen. Cover: (1) the visual style (line / flat / 3D / character-driven — pick + maintain), (2) the recurring element (a character, motif, or treatment that ties them together), (3) per-illustration concept (matched to the screen's message), (4) the colour palette (3–4 from the brand), (5) the pose + composition (clear focal point), (6) the file format (SVG vector + PNG fallback), (7) the dark-mode handling (works on both backgrounds), (8) the future expansion (the style that'll work for screens 5, 6, 7+). Plain English.