manufacturer hover popup + smart back link

Content Partners (and any other) company-hover preview previously used
text-ink / bg-ink / brand-primary utilities that aren't defined in our
Tailwind config, so the popup rendered as white background with no text
color (inheriting near-white text from the dark theme parent). Replaced
every undefined utility with concrete dark-theme colors matching the rest
of the site: #111827 panel, #2a3a50 borders, #e8e8e8 body text, #60a5fa
links, real semi-transparent chip badges.

Manufacturer profile back-link now uses BackLink, a client component that
calls router.back() when we have same-origin history — so clicking the
breadcrumb from the homepage Content Partners hover returns the user to
the homepage instead of dumping them at /manufacturers. Falls through to
the directory link for new-tab opens, search-engine entries, and no-JS.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/app/manufacturers/[slug]/BackLink.tsx

@@ -0,0 +1,36 @@
+"use client";
+
+/**
+ * Smart back link for the manufacturer profile page.
+ *
+ * Renders as a server-rendered <a> linking to the directory so search
+ * engines and no-JS users still get a sensible href. Client-side it
+ * intercepts the click and calls `router.back()` — if the user arrived
+ * here from anywhere on the BB site (homepage Content Partners hover,
+ * an article body link, the directory itself) we'll return them there.
+ * Falls through to the directory only when there is no in-app history.
+ */
+import Link from "next/link";
+import { useRouter } from "next/navigation";
+import type { MouseEvent } from "react";
+
+export default function BackLink() {
+  const router = useRouter();
+  function onClick(e: MouseEvent<HTMLAnchorElement>) {
+    if (typeof window === "undefined") return;
+    // Same-origin Referer means we have somewhere to go back to. The
+    // browser history length > 1 check catches the case where the user
+    // opened the profile in a new tab — in that case we leave the default
+    // navigation (to /manufacturers) alone.
+    const sameOrigin = !!document.referrer && new URL(document.referrer).origin === window.location.origin;
+    if (sameOrigin && window.history.length > 1) {
+      e.preventDefault();
+      router.back();
+    }
+  }
+  return (
+    <Link href="/manufacturers" onClick={onClick} className="hover:text-[#3b82f6]">
+      ← Back
+    </Link>
+  );
+}

src/app/manufacturers/[slug]/page.tsx

@@ -4,6 +4,7 @@ import Link from "next/link";
 import Header from "@/components/Header";
 import Footer from "@/components/Footer";
 import { createClient } from "@/lib/supabase/server";
+import BackLink from "./BackLink";
 
 export const revalidate = 1800;
 
@@ -166,9 +167,7 @@ export default async function ManufacturerProfile({
       />
       <article className="max-w-4xl mx-auto px-4 py-10">
         <nav className="text-xs text-[#888] mb-6">
-          <Link href="/manufacturers" className="hover:text-[#3b82f6]">
-            ← Production Industry Manufacturers
-          </Link>
+          <BackLink />
         </nav>
 
         <header className="flex flex-col sm:flex-row gap-6 mb-8 pb-8 border-b border-[#252525]">