feat: upadted 404 page

src/404.njk

@@ -0,0 +1,25 @@
+---
+layout: layouts/base.njk
+permalink: /404.html
+title: Page not found | River Rooks
+excerpt: The requested page could not be found.
+---
+<section class="not-found tile" aria-labelledby="not-found-title">
+  <header class="tile-header">
+    <span class="tile-title">// ROUTE STATUS</span>
+    <span class="tile-meta">HTTP 404 &bull; NOT FOUND</span>
+  </header>
+
+  <div class="not-found-body">
+    <h1 class="not-found-code" id="not-found-title">404<span class="not-found-cursor" aria-hidden="true">_</span></h1>
+    <div class="not-found-message">
+      <p class="not-found-label">REQUEST FAILED / NO MATCHING ROUTE</p>
+      <h2>Page not found.</h2>
+      <p>The address you requested doesn't point to a page here. Check the URL, or choose a known route below.</p>
+      <nav class="not-found-links" aria-label="Recovery links">
+        <a href="/">&gt; Back to home</a>
+        <a href="/dispatches/">&gt; Browse dispatches</a>
+      </nav>
+    </div>
+  </div>
+</section>

src/assets/css/components/not-found.css

@@ -0,0 +1,86 @@
+/* Missing route: a compact diagnostic panel in the site's tiling vocabulary. */
+.not-found {
+  gap: 0;
+  padding: 20px 24px 28px;
+}
+
+.not-found-body {
+  display: grid;
+  grid-template-columns: minmax(0, 0.8fr) minmax(0, 1fr);
+  align-items: center;
+  gap: 24px;
+  min-height: 320px;
+}
+
+.not-found-code {
+  font-family: var(--font-mono);
+  font-size: clamp(5rem, 14vw, 10rem);
+  line-height: 1;
+  letter-spacing: -0.09em;
+  color: var(--accent-amber);
+  white-space: nowrap;
+}
+
+.not-found-cursor {
+  color: var(--text-muted);
+}
+
+.not-found-message {
+  border-left: 1px solid var(--border-color);
+  padding: 16px 0 16px 24px;
+  max-width: 48ch;
+}
+
+.not-found-label {
+  font: 500 0.75rem var(--font-mono);
+  letter-spacing: 0.06em;
+  color: var(--accent-amber);
+  margin-bottom: 12px;
+}
+
+.not-found-message h2 {
+  font: 700 clamp(1.3rem, 3vw, 2rem) / 1.25 var(--font-mono);
+  margin-bottom: 12px;
+}
+
+.not-found-message > p:not(.not-found-label) {
+  color: var(--text-muted);
+  max-width: 42ch;
+}
+
+.not-found-links {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 8px 24px;
+  margin-top: 24px;
+  font: 500 0.85rem var(--font-mono);
+}
+
+.not-found-links a {
+  color: var(--accent-cyan);
+  text-decoration: none;
+}
+
+.not-found-links a:hover {
+  color: var(--bg-canvas);
+  background: var(--accent-cyan);
+}
+
+@media (max-width: 680px) {
+  .not-found {
+    padding: 16px;
+  }
+
+  .not-found-body {
+    grid-template-columns: 1fr;
+    gap: 8px;
+    min-height: 0;
+    padding: 32px 0 8px;
+  }
+
+  .not-found-message {
+    border-left: 0;
+    border-top: 1px solid var(--border-color);
+    padding: 20px 0 0;
+  }
+}

src/assets/css/main.css

@@ -19,3 +19,4 @@
 @import "./components/code-box.css";
 @import "./components/article.css";
 @import "./components/footer.css";
+@import "./components/not-found.css";