fix(sdk): preserve unquoted escapes in inline styles (#5246)

packages/sdk/src/engine/model.ts

@@ -236,11 +236,11 @@ interface StyleDeclarationScan {
 }
 
 function advanceStyleDeclarationScan(scan: StyleDeclarationScan, ch: string, next: string): void {
+  if (ch === "\\" && next) {
+    scan.skip = true;
+    return;
+  }
   if (scan.quote) {
-    if (ch === "\\" && next) {
-      scan.skip = true;
-      return;
-    }
     if (ch === scan.quote) scan.quote = null;
     return;
   }

packages/sdk/src/engine/mutate.test.ts

@@ -914,6 +914,52 @@ describe("setElementStyles key normalization", () => {
   });
 });
 
+describe("setElementStyles unquoted CSS escapes", () => {
+  it.each([
+    [
+      "semicolon",
+      String.raw`--label: alpha\;beta; width: 120px; color: red`,
+      String.raw`alpha\;beta`,
+    ],
+    [
+      "opening parenthesis",
+      String.raw`--label: alpha\(beta; width: 120px; color: red`,
+      String.raw`alpha\(beta`,
+    ],
+    [
+      "double quote",
+      String.raw`--label: alpha\"beta; width: 120px; color: red`,
+      String.raw`alpha\"beta`,
+    ],
+    [
+      "single quote",
+      String.raw`--label: alpha\'beta; width: 120px; color: red`,
+      String.raw`alpha\'beta`,
+    ],
+  ])("preserves an escaped %s and the following declarations", (_name, style, label) => {
+    const parsed = parseMutable('<div data-hf-id="hf-x" data-hf-root></div>');
+    const el = parsed.document.querySelector('[data-hf-id="hf-x"]');
+    if (!el) throw new Error("missing fixture element");
+    el.setAttribute("style", style);
+    expect(getElementStyles(el)).toMatchObject({ "--label": label, width: "120px", color: "red" });
+    setElementStyles(el, { color: "blue" });
+    expect(getElementStyles(el)).toMatchObject({ "--label": label, width: "120px", color: "blue" });
+  });
+
+  it("treats the semicolon after an escaped backslash as a declaration boundary", () => {
+    const parsed = parseMutable('<div data-hf-id="hf-x" data-hf-root></div>');
+    const el = parsed.document.querySelector('[data-hf-id="hf-x"]');
+    if (!el) throw new Error("missing fixture element");
+    el.setAttribute("style", String.raw`--label: alpha\\; width: 120px; color: red`);
+    setElementStyles(el, { color: "blue" });
+    expect(getElementStyles(el)).toMatchObject({
+      "--label": String.raw`alpha\\`,
+      width: "120px",
+      color: "blue",
+    });
+  });
+});
+
 // ─── setVariableValue ─────────────────────────────────────────────────────────
 
 describe("setVariableValue", () => {

packages/sdk/src/session.render-faithful.test.ts

@@ -185,3 +185,27 @@ describe("serialize() render-faithfulness (WS-F)", () => {
     expect(comp2.getElement("hf-body")?.text).toContain("Round-tripped body");
   });
 });
+
+describe("serialize() preserves unquoted CSS escapes", () => {
+  it.each([
+    String.raw`alpha\;beta`,
+    String.raw`alpha\(beta`,
+    String.raw`alpha\"beta`,
+    String.raw`alpha\'beta`,
+  ])("keeps %s through edit, undo, redo, and saved overrides", async (label) => {
+    const style = `--label: ${label}; width: 120px; color: red`.replace(/"/g, """);
+    const source = `<div data-hf-id="hf-box" data-hf-root style="${style}"></div>`;
+    const comp = await openComposition(source);
+    const expected = { "--label": label, width: "120px", color: "blue" };
+    comp.setStyle("hf-box", { color: "blue" });
+    expect(comp.getElement("hf-box")?.inlineStyles).toMatchObject(expected);
+    comp.undo();
+    expect(comp.getElement("hf-box")?.inlineStyles).toMatchObject({ ...expected, color: "red" });
+    comp.redo();
+    expect(comp.getElement("hf-box")?.inlineStyles).toMatchObject(expected);
+    const reopened = await openComposition(comp.serialize());
+    expect(reopened.getElement("hf-box")?.inlineStyles).toMatchObject(expected);
+    const overrides = await openComposition(source, { overrides: comp.getOverrides() });
+    expect(overrides.getElement("hf-box")?.inlineStyles).toMatchObject(expected);
+  });
+});