Initial portfolio site: Astro + Tailwind MVP

Outcome-led hero, about, grouped skills, experience summary, featured
projects + /projects index, static contact, SEO/OG, dark/light theme.
Dockerfile + nginx config + build script for homelab deploy.

src/pages/404.astro

@@ -0,0 +1,35 @@
+---
+import Layout from "../layouts/Layout.astro";
+---
+
+<Layout title="404 — Not found" path="/404">
+  <section class="nf">
+    <div class="container nf__inner">
+      <p class="eyebrow">Error 404</p>
+      <h1 class="nf__code mono">404</h1>
+      <p class="nf__msg">
+        This route returned no endpoint. The page you're looking for isn't here.
+      </p>
+      <a class="btn btn--primary" href="/">← Back home</a>
+    </div>
+  </section>
+</Layout>
+
+<style>
+  .nf {
+    min-height: 64vh;
+    display: grid;
+    place-items: center;
+    text-align: center;
+  }
+  .nf__code {
+    font-size: var(--step-5);
+    color: var(--accent);
+    margin-block: var(--space-3);
+  }
+  .nf__msg {
+    color: var(--text-dim);
+    max-width: 38ch;
+    margin: 0 auto var(--space-6);
+  }
+</style>