bugfix:The Mintlify navbar (logo + search bar with ⌘K) scrolls away w… (#2445)

* bugfix:The Mintlify navbar (logo + search bar with ⌘K) scrolls away when scrolling down the documentation, so it disappears from view.

* fix(docs): keep navbar visible on scroll (#2445) (thanks @chenyuan99)

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Co-authored-by: vignesh07 <vigneshnatarajan92@gmail.com>

src/docs/terminal-css.test.ts

@@ -0,0 +1,28 @@
+import { readFileSync } from "node:fs";
+import { join } from "node:path";
+import { describe, expect, test } from "vitest";
+
+function readTerminalCss() {
+  // This test is intentionally simple: it guards against regressions where the
+  // docs header stops being sticky because sticky elements live inside an
+  // overflow-clipped container.
+  const path = join(process.cwd(), "docs", "assets", "terminal.css");
+  return readFileSync(path, "utf8");
+}
+
+describe("docs terminal.css", () => {
+  test("keeps the docs header sticky (shell is sticky)", () => {
+    const css = readTerminalCss();
+    expect(css).toMatch(/\.shell\s*\{[^}]*position:\s*sticky;[^}]*top:\s*0;[^}]*\}/s);
+  });
+
+  test("does not rely on making body overflow visible", () => {
+    const css = readTerminalCss();
+    expect(css).not.toMatch(/body\s*\{[^}]*overflow-x:\s*visible;[^}]*\}/s);
+  });
+
+  test("does not make the terminal frame overflow visible (can break layout)", () => {
+    const css = readTerminalCss();
+    expect(css).not.toMatch(/\.shell__frame\s*\{[^}]*overflow:\s*visible;[^}]*\}/s);
+  });
+});