diff --git a/astro.config.mjs b/astro.config.mjs
index 32e2cf1..4859dc5 100644
--- a/astro.config.mjs
+++ b/astro.config.mjs
@@ -38,6 +38,7 @@ export default defineConfig({
             PageTitle: './src/components/PageTitle.astro',
             PageSidebar: './src/components/PageSidebar.astro',
             Footer: './src/components/Footer.astro',
+            Header: './src/components/Header.astro',
           },
           social: [
                 { icon: 'linkedin', label: 'LinkedIn', href: 'https://www.linkedin.com/company/apiopscycles/' },
diff --git a/src/components/Header.astro b/src/components/Header.astro
new file mode 100644
index 0000000..818784e
--- /dev/null
+++ b/src/components/Header.astro
@@ -0,0 +1,124 @@
+---
+import config from 'virtual:starlight/user-config';
+
+import LanguageSelect from 'virtual:starlight/components/LanguageSelect';
+import Search from 'virtual:starlight/components/Search';
+import SiteTitle from 'virtual:starlight/components/SiteTitle';
+import SocialIcons from 'virtual:starlight/components/SocialIcons';
+import MobileMenuToggle from 'virtual:starlight/components/MobileMenuToggle';
+import ThemeSelect from 'virtual:starlight/components/ThemeSelect';
+
+/**
+ * Render the `Search` component if Pagefind is enabled or the default search component has been overridden.
+ */
+const shouldRenderSearch =
+  config.pagefind || config.components.Search !== '@astrojs/starlight/components/Search.astro';
+
+const { hasSidebar } = Astro.locals.starlightRoute;
+---
+
+<div class="header">
+  <div class="title-wrapper sl-flex">
+    <SiteTitle />
+  </div>
+  <div class="sl-flex print:hidden">
+    {shouldRenderSearch && <Search />}
+  </div>
+  <div class="sl-flex md:sl-hidden print:hidden mobile-social">
+    <SocialIcons />
+  </div>
+  <div class="sl-hidden md:sl-flex print:hidden right-group desktop-group">
+    <div class="sl-flex social-icons">
+      <SocialIcons />
+    </div>
+    <ThemeSelect />
+    <LanguageSelect />
+  </div>
+  {hasSidebar && (
+    <div class="sl-flex md:sl-hidden print:hidden mobile-toggle">
+      <MobileMenuToggle />
+    </div>
+  )}
+</div>
+
+<style>
+  @layer starlight.core {
+    .header {
+      display: flex;
+      gap: var(--sl-nav-gap);
+      justify-content: space-between;
+      align-items: center;
+      height: 100%;
+    }
+
+    .title-wrapper {
+      /* Prevent long titles overflowing and covering the search and menu buttons on narrow viewports. */
+      overflow: clip;
+      /* Avoid clipping focus ring around link inside title wrapper. */
+      padding: 0.25rem;
+      margin: -0.25rem;
+      min-width: 0;
+    }
+
+    .right-group,
+    .social-icons {
+      gap: 1rem;
+      align-items: center;
+    }
+
+    .desktop-group .social-icons::after {
+      content: '';
+      height: 2rem;
+      border-inline-end: 1px solid var(--sl-color-gray-5);
+    }
+
+    .mobile-social {
+      gap: 0.75rem;
+      align-items: center;
+    }
+
+    .mobile-social :global(a) {
+      display: inline-flex;
+      align-items: center;
+    }
+
+    .mobile-toggle {
+      align-items: center;
+    }
+
+    :global(nav starlight-menu-button) {
+      display: none;
+    }
+
+    @media (min-width: 50rem) {
+      :global(:root[data-has-sidebar]) {
+        --__sidebar-pad: calc(2 * var(--sl-nav-pad-x));
+      }
+      :global(:root:not([data-has-toc])) {
+        --__toc-width: 0rem;
+      }
+      .header {
+        --__sidebar-width: max(0rem, var(--sl-content-inline-start, 0rem) - var(--sl-nav-pad-x));
+        --__main-column-fr: calc(
+          (
+            100% + var(--__sidebar-pad, 0rem) - var(--__toc-width, var(--sl-sidebar-width)) -
+              (2 * var(--__toc-width, var(--sl-nav-pad-x))) - var(--sl-content-inline-start, 0rem) -
+              var(--sl-content-width)
+          ) / 2
+        );
+        display: grid;
+        grid-template-columns:
+          /* 1 (site title): runs up until the main content column’s left edge or the width of the title, whichever is the largest */
+          minmax(
+            calc(var(--__sidebar-width) + max(0rem, var(--__main-column-fr) - var(--sl-nav-gap))),
+            auto
+          )
+          /* 2 (search box): all free space that is available. */
+          1fr
+          /* 3 (right items): use the space that these need. */
+          auto;
+        align-content: center;
+      }
+    }
+  }
+</style>