Show a clean todo list app feature screen inside a modern smartphone mockup, centered vertically with generous space around it. Place the App Name in the app header and display the Tasks as a simple checklist, with every task visibly checked. Use clear sans-serif typography, compact spacing, rounded task rows, subtle dividers and a small completion indicator that makes the finished state immediately understandable. Set the surrounding background to the Background Color, with soft tonal variation or a very gentle gradient that keeps the phone easy to read. Use balanced studio lighting, a slight three-quarter phone angle, realistic glass and edge reflections, and a crisp product-marketing finish. Keep the interface text sharp and correctly spelled, with no extra labels or invented tasks. Compose the entire feature screenshot in the Format.
Use these details:
App Name: "DoneFlow"
Tasks: ["Review weekly goals", "Reply to client emails", "Plan tomorrow's priorities", "Take an afternoon walk"]
Background Color: "fresh leaf green"
Format: "9:16 vertical"
