diff --git a/README.md b/README.md
index 6e607bd..c296cbf 100644
--- a/README.md
+++ b/README.md
@@ -11,9 +11,11 @@ dark, desktop, and mobile support.
 
 Run `npm install`, `npm run build`, and `npm run check`.
 
-For live preview, set `AERA_TEST_VAULT`, then run `npm run link:vault` and
-`npm run dev`. Changes to `manifest.json` require an Obsidian restart, while
-compiled CSS changes automatically reload in the linked vault.
+For live preview, set `AERA_TEST_VAULT` to a dedicated test vault, then run
+`npm run link:vault` and `npm run dev`. The linker refuses to replace unknown
+notes named `Theme Playground.md` or `Embedded Note.md`. Changes to
+`manifest.json` require an Obsidian restart, while
+compiled CSS automatically reloads in the linked vault.
 
 ## Release assets
 
diff --git a/fixtures/Embedded Note.md b/fixtures/Embedded Note.md
index 49093c5..4fd6bd3 100644
--- a/fixtures/Embedded Note.md	
+++ b/fixtures/Embedded Note.md	
@@ -3,3 +3,5 @@
 这是一篇用于验证 `[[Embedded Note]]` 已解析内部链接与嵌入预览的中文笔记。
 
 返回 [[Theme Playground]]。
+
+<!-- Aera fixture managed by obsidian-aera-theme. -->
diff --git a/fixtures/Theme Playground.md b/fixtures/Theme Playground.md
index ba1f7ac..b01f6b1 100644
--- a/fixtures/Theme Playground.md	
+++ b/fixtures/Theme Playground.md	
@@ -66,3 +66,5 @@ published: 2026-07-16
 演练场以脚注引用结束。[^aera]
 
 [^aera]: Aera 是用于检查 Obsidian 主题的演练 fixture。
+
+<!-- Aera fixture managed by obsidian-aera-theme. -->
diff --git a/scripts/link-vault.mjs b/scripts/link-vault.mjs
index afb144a..084e33b 100644
--- a/scripts/link-vault.mjs
+++ b/scripts/link-vault.mjs
@@ -17,6 +17,8 @@ import { fileURLToPath } from "node:url";
 const modulePath = fileURLToPath(import.meta.url);
 const defaultRepoPath = dirname(dirname(modulePath));
 const fixtureNames = ["Theme Playground.md", "Embedded Note.md"];
+const fixtureOwnershipMarker =
+  "<!-- Aera fixture managed by obsidian-aera-theme. -->";
 
 async function existingPathType(path) {
   try {
@@ -55,6 +57,17 @@ async function assertSafeFixtureTarget(path) {
   throw new Error(`Refusing to replace fixture ${type} at ${path}`);
 }
 
+async function assertManagedFixtureTarget(path) {
+  const existing = await existingPathType(path);
+  if (!existing) return;
+
+  await assertSafeFixtureTarget(path);
+  const contents = await readFile(path, "utf8");
+  if (!contents.trimEnd().endsWith(fixtureOwnershipMarker)) {
+    throw new Error(`Refusing to replace unknown fixture at ${path}`);
+  }
+}
+
 export async function copyFixtureSafely(
   sourcePath,
   destinationPath,
@@ -140,7 +153,7 @@ export async function linkVault(vaultPath, repoPath = defaultRepoPath) {
     source: join(repo, "fixtures", name),
   }));
   for (const { destination } of fixtures) {
-    await assertSafeFixtureTarget(destination);
+    await assertManagedFixtureTarget(destination);
   }
   for (const { destination, source } of fixtures) {
     await copyFixtureSafely(source, destination);
diff --git a/src/editor/_headings.scss b/src/editor/_headings.scss
index a1b2c09..49ebda9 100644
--- a/src/editor/_headings.scss
+++ b/src/editor/_headings.scss
@@ -1,6 +1,6 @@
 body {
   --inline-title-color: var(--text-normal);
-  --inline-title-font: var(--font-text-theme);
+  --inline-title-font: var(--font-text);
   --inline-title-line-height: 1.25;
   --inline-title-size: 2em;
   --inline-title-weight: 650;
diff --git a/tests/editor-inline.test.mjs b/tests/editor-inline.test.mjs
index 00f73c8..a74b3f4 100644
--- a/tests/editor-inline.test.mjs
+++ b/tests/editor-inline.test.mjs
@@ -16,7 +16,7 @@ function assertDeclarations(expected) {
 test("defines the inline title hierarchy", () => {
   assertDeclarations({
     "--inline-title-color": "var(--text-normal)",
-    "--inline-title-font": "var(--font-text-theme)",
+    "--inline-title-font": "var(--font-text)",
     "--inline-title-line-height": "1.25",
     "--inline-title-size": "2em",
     "--inline-title-weight": "650",
diff --git a/tests/link-vault.test.mjs b/tests/link-vault.test.mjs
index 7d83808..1713356 100644
--- a/tests/link-vault.test.mjs
+++ b/tests/link-vault.test.mjs
@@ -28,6 +28,8 @@ import {
 const repoRoot = dirname(fileURLToPath(new URL("../package.json", import.meta.url)));
 const cliPath = join(repoRoot, "scripts/link-vault.mjs");
 const fixtureNames = ["Theme Playground.md", "Embedded Note.md"];
+const fixtureOwnershipMarker =
+  "<!-- Aera fixture managed by obsidian-aera-theme. -->";
 
 async function createVault(t) {
   const vault = await mkdtemp(join(tmpdir(), "aera-vault-"));
@@ -71,6 +73,58 @@ test("linkVault links Aera and copies the playground fixtures", async (t) => {
   }
 });
 
+test("linkVault updates fixtures carrying the Aera ownership marker", async (t) => {
+  const vault = await createVault(t);
+
+  for (const name of fixtureNames) {
+    await writeFile(
+      join(vault, name),
+      `stale fixture\n\n${fixtureOwnershipMarker}\n`,
+    );
+  }
+
+  await linkVault(vault, repoRoot);
+
+  for (const name of fixtureNames) {
+    assert.equal(
+      await readFile(join(vault, name), "utf8"),
+      await readFile(join(repoRoot, "fixtures", name), "utf8"),
+    );
+  }
+});
+
+for (const unknownFixture of fixtureNames) {
+  test(`linkVault rejects an unknown ${unknownFixture} before updating any fixture`, async (t) => {
+    const vault = await createVault(t);
+    const originalContents = new Map();
+
+    for (const name of fixtureNames) {
+      const contents =
+        name === unknownFixture
+          ? `personal ${name} content\n`
+          : `stale owned ${name}\n\n${fixtureOwnershipMarker}\n`;
+      originalContents.set(name, contents);
+      await writeFile(join(vault, name), contents);
+    }
+
+    await assert.rejects(
+      linkVault(vault, repoRoot),
+      new RegExp(`Refusing to replace unknown fixture.*${unknownFixture}`, "i"),
+    );
+
+    for (const name of fixtureNames) {
+      assert.equal(
+        await readFile(join(vault, name), "utf8"),
+        originalContents.get(name),
+      );
+    }
+    assert.equal(
+      (await readdir(vault)).some((name) => /aera.*tmp|\.tmp/i.test(name)),
+      false,
+    );
+  });
+}
+
 test("the playground fixture covers the supported Markdown elements", async () => {
   const playground = await readFile(
     join(repoRoot, "fixtures", "Theme Playground.md"),
@@ -118,6 +172,7 @@ test("the playground fixture covers the supported Markdown elements", async () =
   assert.match(playground, /^!\[\[Embedded Note\]\]$/m);
   assert.match(playground, /^演练场以脚注引用结束。\[\^aera\]$/m);
   assert.match(playground, /^\[\^aera\]: Aera 是用于检查 Obsidian 主题的演练 fixture。$/m);
+  assert.equal(playground.endsWith(`${fixtureOwnershipMarker}\n`), true);
 
   const embedded = await readFile(
     join(repoRoot, "fixtures", "Embedded Note.md"),
@@ -126,6 +181,7 @@ test("the playground fixture covers the supported Markdown elements", async () =
   assert.match(embedded, /^# 嵌入内容$/m);
   assert.match(embedded, /^这是一篇用于验证 `\[\[Embedded Note\]\]` 已解析内部链接与嵌入预览的中文笔记。$/m);
   assert.match(embedded, /^返回 \[\[Theme Playground\]\]。$/m);
+  assert.equal(embedded.endsWith(`${fixtureOwnershipMarker}\n`), true);
 });
 
 for (const fixtureName of fixtureNames) {
diff --git a/theme.css b/theme.css
index f45cab6..cd1d95b 100644
--- a/theme.css
+++ b/theme.css
@@ -72,7 +72,7 @@ body {
 
 body {
   --inline-title-color: var(--text-normal);
-  --inline-title-font: var(--font-text-theme);
+  --inline-title-font: var(--font-text);
   --inline-title-line-height: 1.25;
   --inline-title-size: 2em;
   --inline-title-weight: 650;