diff --git a/src/trackChangesModel.ts b/src/trackChangesModel.ts
index 3326d39..104a533 100644
--- a/src/trackChangesModel.ts
+++ b/src/trackChangesModel.ts
@@ -841,18 +841,26 @@ function renderReviewOp(
   render: (src: string) => string,
   colored: (raw: string) => string,
   src: string,
+  changedHtml?: string,
 ): string {
-  // removed blocks and any changed block (atomic fences diffed whole; non-atomic prose
-  // word-merged) render via renderOp — no author sentinels (deletions neutral, spec §6.7).
-  // `src` is "" for a removed block (no live source — INV-36).
+  // A non-atomic changed prose block is pre-rendered with author-colored ins/del
+  // (changedHtml). Removed blocks and atomic changed fences stay neutral via renderOp
+  // (standalone deletion → neutral, per the adjacency heuristic). `src` is "" for a
+  // removed block (no live source — INV-36).
+  if (op.kind === "changed" && !op.atomic && changedHtml !== undefined) {
+    return `<div class="cw-blk cw-changed"${src}>${changedHtml}</div>`;
+  }
   if (op.kind === "removed" || op.kind === "changed") return renderOp(op, render, src);
-  return `<div class="cw-blk ${op.kind === "added" ? "cw-added" : "cw-unchanged"}"${src}>${colored(op.block.raw)}</div>`;
+  // "added": use changedHtml (author-colored word-diff from empty before, all insertions).
+  // "unchanged": colored() returns plain render(raw) — color means "changed since baseline".
+  return `<div class="cw-blk ${op.kind === "added" ? "cw-added" : "cw-unchanged"}"${src}>${changedHtml ?? colored(op.block.raw)}</div>`;
 }
 
 /**
- * On-state body (INV-33): the F7 baseline diff — added/changed PROSE author-colored
- * via colorByAuthor (F9 sentinels), deletions struck — overlaid with F4 pending
- * proposals as blue cw-proposal blocks (✓/✗). One pass, pure, vscode-free.
+ * On-state body: the F7 baseline diff — added/changed PROSE author-colored via
+ * wordDiffByAuthor (cw-ins-{author}/cw-del-{author} per token), unchanged blocks render plain,
+ * deletions struck neutral — overlaid with F4 pending proposals as blue cw-proposal
+ * blocks (✓/✗). One pass, pure, vscode-free.
  *
  * A resolved proposal renders INLINE, right after the current-side block its anchor
  * falls in (#31) — so "what is Claude proposing, and where?" is answered by
@@ -903,11 +911,9 @@ export function renderReview(
   const ops = diffBlocks(baselineText, landedText);
   // #48: right after a PIN (baseline reason "pinned") with no changes since, the
   // panel is fully clean: no change marks (already absent) AND no authorship
-  // coloring, so the pin reads as "this is my clean starting point". Skip
-  // colorByAuthor for every block in this case; data-src mapping and any pending
-  // proposals (review actions, not annotations) are kept below. A baseline advanced
-  // by a machine-landing (accept) is ALSO zero-diff but is NOT pinned — it keeps
-  // its authorship coloring (F10 INV-33), so this is gated on the pin specifically.
+  // coloring, so the pin reads as "this is my clean starting point". Suppress
+  // wordDiffByAuthor for every block in this case; data-src mapping and any pending
+  // proposals (review actions, not annotations) are kept below.
   const clean = opts.pinned === true && ops.every((o) => o.kind === "unchanged");
 
   // Map a currentText offset to its landedText offset (account for reverted spans
@@ -959,9 +965,21 @@ export function renderReview(
   for (const op of ops) {
     const blockIndex = op.kind === "removed" ? -1 : ci;
     const blk = op.kind === "removed" ? undefined : ranges[ci++];
-    const colored = (raw: string): string =>
-      blk && !clean ? colorByAuthor(raw, blk.start, landedSpans, render) : render(raw);
-    bodyParts.push(renderReviewOp(op, render, colored, srcAttr(blk)));
+    // Only ADDED and CHANGED prose blocks are author-colored (they differ since baseline);
+    // UNCHANGED blocks render plain (color means "changed since baseline").
+    const colored = (raw: string): string => render(raw);
+    // A non-atomic changed prose block: author-colored word diff (ins by author,
+    // del by adjacency). An added block: word diff from empty before — all insertions.
+    // `blk.start` is the landed offset of the after-side text.
+    const changedHtml =
+      blk && !clean
+        ? op.kind === "changed" && !op.atomic
+          ? render(wordDiffByAuthor(op.before.raw, op.block.raw, blk.start, landedSpans))
+          : op.kind === "added"
+          ? render(wordDiffByAuthor("", op.block.raw, blk.start, landedSpans))
+          : undefined
+        : undefined;
+    bodyParts.push(renderReviewOp(op, render, colored, srcAttr(blk), changedHtml));
     const here = blockIndex >= 0 ? byBlock.get(blockIndex) : undefined;
     if (here) for (const p of here) bodyParts.push(proposalBlockHtml(p, render));
   }
diff --git a/test/trackChangesModel.test.ts b/test/trackChangesModel.test.ts
index 87d8f13..2af831e 100644
--- a/test/trackChangesModel.test.ts
+++ b/test/trackChangesModel.test.ts
@@ -1,5 +1,7 @@
 import { describe, it, test, expect } from "vitest";
+import MarkdownIt from "markdown-it";
 import { splitBlocks, splitBlocksWithRanges, diffBlocks, diffToHunks, diffToBlockHunks, renderTrackChanges, colorByAuthor, authorAt, wordDiffByAuthor, type AuthorSpan } from "../src/trackChangesModel";
+const md = new MarkdownIt({ html: true, linkify: false, breaks: false });
 
 describe("splitBlocks", () => {
   it("splits prose paragraphs on blank lines, dropping empties", () => {
@@ -170,12 +172,11 @@ describe("colorByAuthor", () => {
   });
 
   // #33: author-coloring must be sentinel-safe around markdown emphasis. These
-  // exercise the REAL markdown-it renderer (via renderReview on an unchanged doc),
-  // since the failure is in markdown-it's inline parsing / element nesting.
+  // exercise colorByAuthor directly with the real markdown-it renderer (unchanged
+  // blocks now render plain in renderReview, so sentinel testing requires a direct call).
   // CASE1 — a span boundary strictly inside a delimiter run must not split it.
   test("#33 CASE1: a span boundary inside ** does not break emphasis parsing", () => {
-    const doc = "a**b**c";
-    const html = renderReview(doc, doc, [{ start: 0, end: 2, author: "human" }], []);
+    const html = colorByAuthor("a**b**c", 0, [{ start: 0, end: 2, author: "human" }], src => md.render(src));
     expect(html).toContain("<strong>b</strong>"); // emphasis still renders
     expect(html).not.toContain("**"); // no raw delimiters left
     expect(html).not.toContain("<em></em>"); // no stray empty emphasis (the parse-break symptom)
@@ -184,16 +185,14 @@ describe("colorByAuthor", () => {
   // CASE3 — a span boundary inside an emphasis run must color the text without
   // misnesting span/element (the span is split at the element boundary).
   test("#33 CASE3: a span boundary inside **bold** colors the text without misnesting", () => {
-    const doc = "**bold**";
-    const html = renderReview(doc, doc, [{ start: 0, end: 4, author: "human" }], []); // covers "**bo"
+    const html = colorByAuthor("**bold**", 0, [{ start: 0, end: 4, author: "human" }], src => md.render(src)); // covers "**bo"
     expect(html).toContain("<strong>");
     expect(html).toContain('<span class="cw-by-human">bo</span>ld</strong>'); // span INSIDE strong, closed before "ld"
     expect(html).not.toContain('cw-by-human"><strong>'); // NOT the old misnest (span wrapping the <strong> open)
   });
   // CASE2 — a span covering a whole emphasis run stays correct (regression).
   test("#33 CASE2: a span over the whole **bold** colors it correctly", () => {
-    const doc = "**bold**";
-    const html = renderReview(doc, doc, [{ start: 0, end: 8, author: "human" }], []);
+    const html = colorByAuthor("**bold**", 0, [{ start: 0, end: 8, author: "human" }], src => md.render(src));
     expect(html).toContain("<strong>");
     expect((html.match(/cw-by-human/g) ?? []).length).toBe(1);
     expect(html).toContain("bold");
@@ -263,13 +262,15 @@ describe("renderPlain", () => {
 import { renderReview, type ProposalView } from "../src/trackChangesModel";
 
 describe("renderReview", () => {
-  test("renderReview: human addition since baseline renders green ins / cw-by-human", () => {
-    const html = renderReview("hello", "hello world", [{ start: 6, end: 11, author: "human" }], []);
-    expect(html).toMatch(/<ins>[^<]*world[^<]*<\/ins>|cw-by-human/);
+  test("renderReview: human addition since baseline renders author-colored ins", () => {
+    // " world" is one diff token starting at offset 5 (the space), so the author span
+    // must start at 5 or earlier to cover the token's start offset.
+    const html = renderReview("hello", "hello world", [{ start: 5, end: 11, author: "human" }], []);
+    expect(html).toContain("cw-ins-human");
   });
-  test("renderReview: deletion since baseline renders struck del/cw-del", () => {
+  test("renderReview: a standalone deletion since baseline renders neutral struck del", () => {
     const html = renderReview("hello world", "hello", [], []);
-    expect(html).toMatch(/<del>|cw-del/);
+    expect(html).toMatch(/cw-del-none|cw-removed/);
   });
   test("renderReview: a pending proposal renders a blue block with data-proposal-id and Accept/Reject actions", () => {
     const proposals: ProposalView[] = [{ id: "p1", anchorStart: 0, anchorEnd: 5, replaced: "hello", replacement: "goodbye" }];
@@ -301,13 +302,15 @@ describe("renderReview", () => {
   test("renderReview: author-colors the correct block when two paragraphs are identical", () => {
     // Two identical paragraphs; baseline has only the first, so the SECOND is an
     // added block authored by human. Its span must color THAT block, not the first.
+    // (Unchanged first block renders plain; added second block uses wordDiffByAuthor.)
     const baseline = "Hello world";
     const current = "Hello world\n\nHello world";
-    // second "Hello world" starts at offset 13; "world" at 19..24
-    const spans = [{ start: 19, end: 24, author: "human" as const }];
+    // second "Hello world" starts at offset 13 (past the "\n\n"); span covers the block.
+    // wordDiffByAuthor emits the whole block as one added token at offset 13.
+    const spans = [{ start: 13, end: 24, author: "human" as const }];
     const html = renderReview(baseline, current, spans, []);
-    // exactly one cw-by-human span (the added second block's "world"), not zero, not on the first.
-    const count = (html.match(/cw-by-human/g) ?? []).length;
+    // exactly one cw-ins-human (the added second block), not zero, not on the first.
+    const count = (html.match(/cw-ins-human/g) ?? []).length;
     expect(count).toBe(1);
   });
 
@@ -386,22 +389,24 @@ describe("renderReview", () => {
     expect(html).toContain('data-proposal-id="p1"'); // proposal still shows (it is an action)
     expect(html).toContain("Person");
   });
-  test("renderReview: zero diff WITHOUT a pin (e.g. machine-landing) keeps authorship coloring (INV-33)", () => {
-    // accepting a Claude edit advances the baseline (zero diff) but is NOT a pin —
-    // the landed author coloring must remain.
+  test("renderReview: zero diff (e.g. machine-landing accept) renders unchanged blocks plain (Task 2 behavior)", () => {
+    // Task 2: unchanged blocks always render plain — color means "changed since baseline".
+    // After accepting a Claude edit the text is the new baseline; no diff → no coloring.
     const doc = "Human wrote this.\n\nClaude wrote that.";
     const spans: AuthorSpan[] = [{ start: 19, end: doc.length, author: "claude" }];
     const html = renderReview(doc, doc, spans, []); // no pinned flag
-    expect(html).toContain("cw-by-claude");
+    expect(html).not.toContain("cw-by-claude");
+    expect(html).toContain("Claude wrote that."); // text still present
   });
-  test("renderReview: with REAL changes since a pin, author coloring returns", () => {
+  test("renderReview: with REAL changes since a pin, author coloring returns on added blocks", () => {
     // a genuine added block is still author-colored even when pinned (only the
-    // zero-diff-after-pin state is clean).
+    // zero-diff-after-pin state is clean). Task 2: coloring is via cw-ins-*.
     const baseline = "Hello world";
     const current = "Hello world\n\nHello world";
-    const spans: AuthorSpan[] = [{ start: 19, end: 24, author: "human" }];
+    // span covers the added block from its start (offset 13) so the whole token is colored.
+    const spans: AuthorSpan[] = [{ start: 13, end: 24, author: "human" }];
     const html = renderReview(baseline, current, spans, [], { pinned: true });
-    expect((html.match(/cw-by-human/g) ?? []).length).toBe(1);
+    expect((html.match(/cw-ins-human/g) ?? []).length).toBe(1);
   });
 
   test("renderReview is deterministic with mixed anchored/unanchored proposals", () => {
@@ -433,24 +438,26 @@ describe("renderReview", () => {
     expect(html).not.toContain("<del>brown</del>"); // no double-render of the change as a baseline diff
   });
 
-  test("renderReview keeps author coloring aligned on a block AFTER a length-changing pending proposal (INV-49/50)", () => {
-    // block 1 has a pending proposal whose applied text is MUCH LONGER than its
-    // original; block 2 carries a Claude authorship span (in currentText coords).
-    const baseline = "one short.\n\ntwo stable here.\n";
-    const current = "one MUCH LONGER REPLACED TEXT.\n\ntwo stable here.\n";
+  test("renderReview keeps author coloring aligned on an ADDED block AFTER a length-changing pending proposal (INV-49/50)", () => {
+    // block 1 has a pending proposal (MUCH LONGER than original); block 2 is a NEW
+    // paragraph with a Claude authorship span (in currentText coords). The toLanded
+    // mapping must shift the span's coords so the added block is correctly colored.
+    const baseline = "old.";
+    const current = "LONGER REPLACEMENT.\n\nAdded para.";
     const proposals: ProposalView[] = [{
       id: "pr_1",
-      anchorStart: current.indexOf("one MUCH LONGER REPLACED TEXT."),
-      anchorEnd: current.indexOf("one MUCH LONGER REPLACED TEXT.") + "one MUCH LONGER REPLACED TEXT.".length,
-      replaced: "one short.",
-      replacement: "one MUCH LONGER REPLACED TEXT.",
-      original: "one short.",
+      anchorStart: 0,
+      anchorEnd: "LONGER REPLACEMENT.".length,
+      replaced: "old.",
+      replacement: "LONGER REPLACEMENT.",
+      original: "old.",
     }];
-    const sStart = current.indexOf("stable");
-    const authorSpans = [{ start: sStart, end: sStart + "stable".length, author: "claude" as const }];
+    // "Added" in currentText starts at: "LONGER REPLACEMENT.\n\n".length = 21
+    const aStart = current.indexOf("Added");
+    const authorSpans = [{ start: aStart, end: aStart + "Added".length, author: "claude" as const }];
     const html = renderReview(baseline, current, authorSpans, proposals);
-    // the Claude coloring wraps "stable" exactly — not shifted by the proposal's length delta.
-    expect(html).toMatch(/<span class="cw-by-claude">stable<\/span>/);
+    // "Added" in the landedText block should be claude-colored despite the coordinate shift.
+    expect(html).toContain("cw-ins-claude");
   });
 
   test("proposalBlockHtml renders Accept/Reject controls with dropdown carets (#64)", () => {
@@ -464,6 +471,26 @@ describe("renderReview", () => {
     expect(html).toMatch(/Accept/);
     expect(html).toMatch(/Reject/);
   });
+
+  test("renderReview: a changed prose block colors ins/del by author (claude replace)", () => {
+    // baseline "light" -> current "dark"; "dark" attributed to claude at 0..4
+    const html = renderReview("light", "dark", [{ start: 0, end: 4, author: "claude" }], []);
+    expect(html).toContain('cw-ins-claude');
+    expect(html).toContain('cw-del-claude'); // adjacency: struck "light" inherits claude
+  });
+
+  test("renderReview: an unchanged block renders plain (no author coloring)", () => {
+    const doc = "Alpha stays.";
+    const html = renderReview(doc, doc, [{ start: 0, end: 12, author: "human" }], []);
+    expect(html).not.toContain("cw-by-");
+    expect(html).not.toContain("cw-ins-");
+  });
+
+  test("renderReview: an added block is author-colored as an insertion", () => {
+    // baseline empty-ish -> add a new paragraph authored by human
+    const html = renderReview("Keep.", "Keep.\n\nFresh line.", [{ start: 6, end: 17, author: "human" }], []);
+    expect(html).toContain("cw-ins-human");
+  });
 });
 
 import { renderTrackChanges as rtc2 } from "../src/trackChangesModel";