Constant LEAD_GAP 

pub const LEAD_GAP: f64 = _; // 16f64

Between the pill and whatever stands before it in the row: the window’s controls are a section of their own, apart from the app’s by the gap between sections and by the glass the app’s ground has no part of, never by a drawn line. One step below the gap between groups, so the app’s content keeps the room it names its place with in a narrow window.