The in-content header strip showed the app name + version, duplicating the OS window title (setWindowTitle). With the 设置 button already gone it had no other purpose, so remove it (and its styles / unused _HEADER_HEIGHT). Name and version stay visible via the OS title bar; the work area gains ~40px. Docs: UI design 3 (layout) and 4.1 (title bar), tasks.md 17.7. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>