diff --git a/docs/branch-review-records/2c6a919bc949df279d074bdf810c92f2cb5a090b3bd4b521a833f0baa002e0e3.record.md b/docs/branch-review-records/2c6a919bc949df279d074bdf810c92f2cb5a090b3bd4b521a833f0baa002e0e3.record.md
new file mode 100644
index 0000000000..291aa1803d
--- /dev/null
+++ b/docs/branch-review-records/2c6a919bc949df279d074bdf810c92f2cb5a090b3bd4b521a833f0baa002e0e3.record.md
@@ -0,0 +1 @@
+| 2026-08-13 | codex/performance-css-delivery | a324e067d2055fa3e32dd7a039c5e66a62bef3b9 | cold mobile CSS and font delivery | No unresolved findings; review added theme-aware responsive mockup utilities and corrected stale font commentary | build passed (1712 pages); CSS 302113 raw/46203 gzip; contract 2/2; production style 9/9; mockup 15/15; format/issues/ledger passed |
diff --git a/docs/branch-review-records/e9ef965f3b9bffc0aef79a3be4d3c206f04207ac0e1b2d8696bb3f657b7df90a.record.md b/docs/branch-review-records/e9ef965f3b9bffc0aef79a3be4d3c206f04207ac0e1b2d8696bb3f657b7df90a.record.md
new file mode 100644
index 0000000000..c573ff657c
--- /dev/null
+++ b/docs/branch-review-records/e9ef965f3b9bffc0aef79a3be4d3c206f04207ac0e1b2d8696bb3f657b7df90a.record.md
@@ -0,0 +1 @@
+| 2026-08-13 | codex/performance-css-delivery | aa935df8fa13245af948c4574d791fe31f270d03 | cold mobile CSS and font delivery | No unresolved findings after clean current-main sync; shared header changes pass both production and mockup journeys | production style 9/9; mockup 15/15; contract rerun coordinator-blocked after prior 2/2 pass; no changed-path overlap |
diff --git a/docs/outstanding-issues-inbox/66f364c0-5612-449b-9046-94b4dab0b152.json b/docs/outstanding-issues-inbox/66f364c0-5612-449b-9046-94b4dab0b152.json
new file mode 100644
index 0000000000..183374266b
--- /dev/null
+++ b/docs/outstanding-issues-inbox/66f364c0-5612-449b-9046-94b4dab0b152.json
@@ -0,0 +1,12 @@
+{
+  "version": 1,
+  "id": "66f364c0-5612-449b-9046-94b4dab0b152",
+  "createdOn": "2026-08-13",
+  "action": "update",
+  "payload": {
+    "id": "#117",
+    "summary": "All live mobile routes breach LCP; shared render-blocking CSS and font are the current bottleneck",
+    "detail": "PR #1915 is merged and deployed at exact Railway SHA ca788d41e1e6b64dc6b9bc63609074d92470d7e7. Three-sample live medians on that SHA are Documents 3611 ms, DSM 3600 ms, Forms 3715 ms, root 3948 ms, Therapy 3543 ms, and Services 3791 ms; desktop LCP is 584-691 ms and CLS is within the mobile rule. Trace attribution shows LCP equals FCP, TTFB is only 267-316 ms, and the shared render-blocking stylesheet plus preloaded 28 KB Geist font dominate cold mobile paint. The follow-up branch removes mockup-only Tailwind vocabulary from production CSS (367,050 to 302,113 raw bytes; 55,140 to 46,152 gzip) while retaining a complete route-only mockup sheet. It keeps the display-swap body font preloaded because two hosted Lighthouse runs showed that removing it delayed text LCP, while the non-LCP mono font remains on-demand. Next: merge/deploy that exact SHA, rerun the complete live matrix, then attribute remaining shared JS/hydration cost if any route still exceeds 2500 ms. Therapy field safety review remains required for search/pathways. INP remains unverified because Lighthouse does not measure it and no usable CrUX result exists. Stop: do not strip clinical fields, weaken the Lighthouse budget, or claim an INP pass.",
+    "source": "PR #1915; live Web Vitals runs 31704500966 and 31704504389; codex/performance-css-delivery"
+  }
+}
diff --git a/docs/outstanding-issues-inbox/f4b9c833-03f4-40bd-9537-90501c1287c4.json b/docs/outstanding-issues-inbox/f4b9c833-03f4-40bd-9537-90501c1287c4.json
new file mode 100644
index 0000000000..fd49b9f967
--- /dev/null
+++ b/docs/outstanding-issues-inbox/f4b9c833-03f4-40bd-9537-90501c1287c4.json
@@ -0,0 +1,10 @@
+{
+  "version": 1,
+  "id": "f4b9c833-03f4-40bd-9537-90501c1287c4",
+  "createdOn": "2026-08-13",
+  "action": "cancel",
+  "payload": {
+    "requestId": "67f9ce93-caf5-4cd4-89e1-742e61ce882a",
+    "reason": "Superseded by exact deployed-SHA live measurements and the shared CSS/font remediation."
+  }
+}
diff --git a/src/app/globals.css b/src/app/globals.css
index 346265a373..e2e1b64419 100644
--- a/src/app/globals.css
+++ b/src/app/globals.css
@@ -1,4 +1,9 @@
 @import "tailwindcss";
+/* Design-scratch routes have their own route-scoped utility sheet. Keeping
+   their rapidly growing utility vocabulary out of every production page cuts
+   the shared render-blocking stylesheet without changing mockup rendering. */
+@source not "./mockups";
+@source not "../components/**/*mockup*";
 /* Opt-in v2 design-system token layer. Every rule is scoped to `.ckb-v2`, so
    importing it cannot change any surface that does not carry the class. */
 @import "./ckb-v2-tokens.css";
diff --git a/src/app/layout.tsx b/src/app/layout.tsx
index 817658f0be..0c8308d27b 100644
--- a/src/app/layout.tsx
+++ b/src/app/layout.tsx
@@ -47,7 +47,7 @@ const geistMono = localFont({
   // The mono face is only used deep in the UI (tabular figures, `kbd`, code) and
   // never in initial/LCP text, so don't preload it on every route — it competes
   // for the critical-path connection. It still loads on-demand via `swap` when
-  // first painted. The sans face keeps the default preload.
+  // first painted, while the body sans face remains preloaded for LCP text.
   preload: false,
 });
 
diff --git a/src/app/mockups/layout.tsx b/src/app/mockups/layout.tsx
index ec21ee5a5b..18e038c550 100644
--- a/src/app/mockups/layout.tsx
+++ b/src/app/mockups/layout.tsx
@@ -5,6 +5,7 @@ import type { ReactNode } from "react";
 import { mockupsEnabled } from "@/lib/env";
 
 import { MockupsLayoutClient } from "./mockups-layout-client";
+import "./mockups.css";
 
 // Design-exploration prototypes: shipped for shareability, but never indexed
 // (belt-and-braces alongside the robots.ts /mockups/ disallow).
diff --git a/src/app/mockups/mockups.css b/src/app/mockups/mockups.css
new file mode 100644
index 0000000000..7647cdbbff
--- /dev/null
+++ b/src/app/mockups/mockups.css
@@ -0,0 +1,9 @@
+@import "tailwindcss/utilities.css" layer(utilities) source(none);
+@reference "../globals.css";
+
+/* Re-emit the complete utility vocabulary for mockup routes. This preserves
+   Tailwind's responsive ordering when a mockup shares shell components with
+   production. The complete theme-aware sheet retains Tailwind's own base and
+   responsive ordering without overriding inline theming on later live routes. */
+@source "../";
+@source "../../components";
diff --git a/tests/css-delivery-contract.test.ts b/tests/css-delivery-contract.test.ts
new file mode 100644
index 0000000000..033ef023fc
--- /dev/null
+++ b/tests/css-delivery-contract.test.ts
@@ -0,0 +1,30 @@
+import { readFileSync } from "node:fs";
+import { resolve } from "node:path";
+import { describe, expect, it } from "vitest";
+
+const read = (path: string) => readFileSync(resolve(process.cwd(), path), "utf8");
+
+describe("cold-load CSS and font delivery", () => {
+  it("keeps mockup-only Tailwind utilities out of the production global sheet", () => {
+    const globals = read("src/app/globals.css");
+    const mockups = read("src/app/mockups/mockups.css");
+    const layout = read("src/app/mockups/layout.tsx");
+
+    expect(globals).toContain('@source not "./mockups";');
+    expect(globals).toContain('@source not "../components/**/*mockup*";');
+    expect(mockups).toContain('@import "tailwindcss/utilities.css" layer(utilities) source(none);');
+    expect(mockups).not.toMatch(/source\(none\)\s+important/);
+    expect(mockups).toContain('@reference "../globals.css";');
+    expect(mockups).toContain('@source "../";');
+    expect(mockups).toContain('@source "../../components";');
+    expect(layout).toContain('import "./mockups.css";');
+  });
+
+  it("keeps the display-swap body font preloaded for LCP text", () => {
+    const rootLayout = read("src/app/layout.tsx");
+    const geistSans = rootLayout.slice(rootLayout.indexOf("const geistSans"), rootLayout.indexOf("const geistMono"));
+
+    expect(geistSans).toContain('display: "swap"');
+    expect(geistSans).not.toContain("preload: false");
+  });
+});
diff --git a/tests/ui-tools-search-mode-mockup.spec.ts b/tests/ui-tools-search-mode-mockup.spec.ts
index f2c5cc8dd3..f1870b2a93 100644
--- a/tests/ui-tools-search-mode-mockup.spec.ts
+++ b/tests/ui-tools-search-mode-mockup.spec.ts
@@ -75,6 +75,23 @@ test.describe("Perfected Tools results mode mockup @mockup", () => {
     await expectNoHorizontalOverflow(page);
   });
 
+  test("does not let persisted mockup utilities override live-route inline themes", async ({ page }) => {
+    const mockup = await gotoMockup(page, 1440);
+
+    await mockup.getByRole("link", { name: "Colour coding reference" }).click();
+    await expect(page).toHaveURL(/\/reference\/colour-coding$/);
+    await expect(page.getByRole("heading", { level: 1, name: "Colour coding reference" })).toBeVisible();
+
+    const inlineBorderColor = await page.evaluate(() => {
+      const themedCard = document.createElement("div");
+      themedCard.className = "border border-[color:var(--border)]";
+      themedCard.style.borderTopColor = "rgb(1, 2, 3)";
+      document.body.append(themedCard);
+      return window.getComputedStyle(themedCard).borderTopColor;
+    });
+    expect(inlineBorderColor).toBe("rgb(1, 2, 3)");
+  });
+
   test("desktop details use inline semantics and preserve visible programmatic focus", async ({ page }) => {
     const mockup = await gotoMockup(page, 1440);
     const details = mockup.getByRole("button", { name: "View details for Differentials" });