diff --git a/web/canvas.ts b/web/canvas.ts
index 159b11b..bf2ff5d 100644
--- a/web/canvas.ts
+++ b/web/canvas.ts
@@ -213,25 +213,34 @@ export function paintCanvas(document: Document, canvas: Canvas): () => void {
     if (!element) continue;
 
     const previousPosition = element.style.position;
-    const previousMargin = element.style.margin;
 
     // `relative` so the label and the controls can be placed against this band rather than the page.
     element.style.position = 'relative';
-    // Room for the outline and the label above it, so two bands in a row do not touch. Kept inline
-    // because it is layout and must hold whether or not anything is hovered — the outline itself is in
-    // the stylesheet, INSET, so a band filling the column never draws past the measure.
-    element.style.margin = '2.5rem 0';
 
+    /*
+      NO margin. There was `2.5rem 0` here, to make room for the label above each band.
+
+      That is 40 pixels above and below every section that the real page does not have, and it made the
+      preview overstate the spacing of every page in the site — on the one screen whose entire purpose
+      is to show what the page looks like. It was reported as "there is a lot more space between the
+      logo and the text in the admin", which is exactly what it was.
+
+      A preview may draw ON the page. It may not CHANGE it. Everything this file adds is now either
+      absolutely positioned or an outline, both of which take no layout space, and the label moved
+      inside the band it names — see the bar below.
+    */
     undo.push(() => {
       element.style.position = previousPosition;
-      element.style.margin = previousMargin;
     });
 
     const bar = document.createElement('div');
     bar.setAttribute(MARK, 'section-bar');
     style(bar, [
       'position:absolute',
-      'top:-1.75rem',
+      // INSIDE the band, not above it. Above needed 40px of margin the page does not have; the bar is
+      // hover-only, so overlaying the first line of a band for as long as the pointer is on it costs
+      // nothing and lying about the layout costs the preview its whole point.
+      'top:0',
       'left:0',
       'right:0',
       'display:flex',