404: use inline style-tag instead of per-element styles

layouts/404.html

 {{ define "main"}}
 <main class="container my-3 text-light">
-  <div class="text-center" style="text-shadow: 0 0 0.25em #111, 0 0 0.5em #111, 0 0 1em #111, 0 0 2em #111, 0 0 4em #111;">
+  <div class="text-center">
     <h1 class="display-2">404</h1>
     <p class="lead">Page not found :(</p>
     <p>The requested page could not be found.</p>
@@ -15,9 +15,22 @@
     believe this is a mistake.
   </div>
 </main>
-<div class="position-fixed w-100 user-select-none" style="background-color: #111; z-index:-1">
-  <pre style="color: #333">
+<div id="bg" class="position-fixed w-100 user-select-none">
+  <pre>
     {{readFile "/layouts/404-panic.txt"}}
   </pre>
 </div>
+<style>
+  main div:first-child {
+    text-shadow: 0 0 0.25em #111, 0 0 0.5em #111, 0 0 1em #111, 0 0 2em #111, 0 0 4em #111;
+  }
+  #bg {
+    background-color: #111;
+    z-index: -1;
+  }
+  pre {
+    color: #333;
+  }
+</style>
+
 {{ end }}