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diff --git a/src/templates/assets/javascripts/components/header/title/index.ts b/src/templates/assets/javascripts/components/header/title/index.ts
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+++ b/src/templates/assets/javascripts/components/header/title/index.ts
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+/*
+ * Copyright (c) 2016-2023 Martin Donath <martin.donath@squidfunk.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+import {
+  EMPTY,
+  Observable,
+  Subject,
+  defer,
+  distinctUntilKeyChanged,
+  finalize,
+  map,
+  tap
+} from "rxjs"
+
+import {
+  Viewport,
+  getElementSize,
+  getOptionalElement,
+  watchViewportAt
+} from "~/browser"
+
+import { Component } from "../../_"
+import { Header } from "../_"
+
+/* ----------------------------------------------------------------------------
+ * Types
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Header
+ */
+export interface HeaderTitle {
+  active: boolean                      /* Header title is active */
+}
+
+/* ----------------------------------------------------------------------------
+ * Helper types
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Watch options
+ */
+interface WatchOptions {
+  viewport$: Observable<Viewport>      /* Viewport observable */
+  header$: Observable<Header>          /* Header observable */
+}
+
+/**
+ * Mount options
+ */
+interface MountOptions {
+  viewport$: Observable<Viewport>      /* Viewport observable */
+  header$: Observable<Header>          /* Header observable */
+}
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Watch header title
+ *
+ * @param el - Heading element
+ * @param options - Options
+ *
+ * @returns Header title observable
+ */
+export function watchHeaderTitle(
+  el: HTMLElement, { viewport$, header$ }: WatchOptions
+): Observable<HeaderTitle> {
+  return watchViewportAt(el, { viewport$, header$ })
+    .pipe(
+      map(({ offset: { y } }) => {
+        const { height } = getElementSize(el)
+        return {
+          active: y >= height
+        }
+      }),
+      distinctUntilKeyChanged("active")
+    )
+}
+
+/**
+ * Mount header title
+ *
+ * This function swaps the header title from the site title to the title of the
+ * current page when the user scrolls past the first headline.
+ *
+ * @param el - Header title element
+ * @param options - Options
+ *
+ * @returns Header title component observable
+ */
+export function mountHeaderTitle(
+  el: HTMLElement, options: MountOptions
+): Observable<Component<HeaderTitle>> {
+  return defer(() => {
+    const push$ = new Subject<HeaderTitle>()
+    push$.subscribe({
+
+      /* Handle emission */
+      next({ active }) {
+        el.classList.toggle("md-header__title--active", active)
+      },
+
+      /* Handle complete */
+      complete() {
+        el.classList.remove("md-header__title--active")
+      }
+    })
+
+    /* Obtain headline, if any */
+    const heading = getOptionalElement(".md-content h1")
+    if (typeof heading === "undefined")
+      return EMPTY
+
+    /* Create and return component */
+    return watchHeaderTitle(heading, options)
+      .pipe(
+        tap(state => push$.next(state)),
+        finalize(() => push$.complete()),
+        map(state => ({ ref: el, ...state }))
+      )
+  })
+}