Give the writing a page to sit on, so the empty half means something

The text was capped at a readable width inside a much wider pane, which
left a large void on the right with nothing to explain it. The page is
now a drawn surface: the writing sits on it with a margin, and the space
that was empty is that margin.

Page boundaries used to be a hairline. They are a dashed band now, with
the next page's number in the margin beside it, so a boundary reads as
one page ending rather than as a rule in the text.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

frontend/src/features/notes/NoteEditor.jsx

@@ -100,6 +100,10 @@ export function NoteEditor({
       muted: dark ? "#8b949e" : "#656d76",
       active: dark ? "#388bfd" : "#0969da",
       faint: dark ? "#484f58" : "#afb8c1",
+      /* A shade apart from the desk it lies on — enough to read as a surface,
+         not so much that it glares in a dark room. */
+      pageBg: dark ? "#131922" : "#ffffff",
+      desk: dark ? "#0b0f14" : "#e9ecef",
     }),
     [dark]
   );
@@ -498,11 +502,7 @@ export function NoteEditor({
          * width a property of the window, which is what it always looked like. */
         flex: 1,
         minWidth: 0,
-        background: isMobileViewport
-          ? T.bg
-          : dark
-            ? "linear-gradient(180deg,#0f141b 0%,#0d1117 60%)"
-            : "linear-gradient(180deg,#f8fafd 0%,#eef3f8 70%)",
+        background: isMobileViewport ? T.pageBg : T.desk,
       }}
     >
       {/* Main toolbar */}
@@ -716,41 +716,65 @@ export function NoteEditor({
             padding: isMobileViewport ? "10px 0 18px" : "18px 0 28px",
           }}
         >
+          {/* The page is a surface, always.
+              With the text capped at a readable measure and nothing behind it,
+              the right 40% of the pane was simply void. A page gives that space
+              a meaning — it is the margin — and it is what lets "page 2" show as
+              a page rather than as a line across an empty field. */}
           <div
             style={{
               position: "relative",
-              // Without a page the column is as wide as it needs to be to read
-              // comfortably, and centred; with one it is the canvas's page.
-              // The text caps its own width in the stylesheet, so this is only
-              // the page when there is one.
-              width: needsPage ? stageSize.w : "100%",
-              minHeight: needsPage ? stageSize.h : undefined,
-              margin: "0 auto",
-              background: needsPage ? T.bg : "transparent",
-              border: needsPage && !isMobileViewport ? `1px solid ${T.border}` : "none",
-              borderRadius: needsPage && !isMobileViewport ? 14 : 0,
-              boxShadow: needsPage && !isMobileViewport ? "0 16px 36px rgba(0,0,0,0.14)" : "none",
+              width: stageSize.w,
+              maxWidth: "100%",
+              minHeight: stageSize.h,
+              margin: isMobileViewport ? "0 auto" : "0 0 0 28px",
+              background: T.pageBg,
+              border: isMobileViewport ? "none" : `1px solid ${T.border}`,
+              borderRadius: isMobileViewport ? 0 : 6,
+              boxShadow: isMobileViewport ? "none" : "0 6px 20px rgba(0,0,0,0.16)",
             }}
           >
-            {/* A hairline where each page ends, so the count in the toolbar
-                corresponds to something you can see. Drawn behind the text and
-                deaf to the pointer — it marks the paper, it is not part of it. */}
-            {pages.count > 1 && mode === "text" && (
+            {/* Where one page ends and the next begins.
+                A band rather than a hairline, with the new page's number set in
+                the margin — the count in the toolbar should correspond to
+                something that reads as a page, not to a line across a field.
+                The text flows on through: the note is one document, and a real
+                page break would mean laying the text out ourselves. */}
+            {Array.from({ length: Math.max(0, pages.count - 1) }, (_, i) => (
               <div
+                key={i}
                 aria-hidden
+                data-page-break={i + 2}
                 style={{
                   position: "absolute",
-                  inset: 0,
+                  left: 0,
+                  right: 0,
+                  top: stageSize.h * (i + 1),
+                  height: 0,
                   pointerEvents: "none",
-                  backgroundImage: `linear-gradient(to bottom, transparent calc(100% - 1px), ${T.border} 100%)`,
-                  backgroundSize: `100% ${stageSize.h}px`,
-                  opacity: 0.55,
+                  borderTop: `1px dashed ${T.border}`,
                 }}
-              />
-            )}
+              >
+                <span
+                  style={{
+                    position: "absolute",
+                    right: 14,
+                    top: 8,
+                    fontSize: 10.5,
+                    letterSpacing: 0.5,
+                    color: T.faint,
+                    background: T.pageBg,
+                    padding: "0 4px",
+                  }}
+                >
+                  Page {i + 2}
+                </span>
+              </div>
+            ))}
+
             <div
               style={{
-                minHeight: needsPage ? stageSize.h : undefined,
+                minHeight: stageSize.h,
                 width: "100%",
                 pointerEvents: mode === "text" ? "auto" : "none",
               }}
@@ -759,7 +783,7 @@ export function NoteEditor({
                 editor={textEditor}
                 dark={dark}
                 font={noteFont}
-                minHeight={needsPage ? stageSize.h : 0}
+                minHeight={stageSize.h}
                 onOpenNote={onOpenNote}
                 resolveLinkLabel={resolveLinkLabel}
               />