refactor 404 page to align with vocab markup

Author: Queen-codes

src/404.html

@@ -132,23 +132,13 @@ <h2>Our Work Relies On You!</h2>
 
     <main>
       <span id="main-content-marker"></span>
-      <div class="body-second-sect">
-        <h2>404: Not Found</h2>
-        <p>
-          <strong
-            >Go to the <a href="/">CC Search Portal home page</a>.</strong
-          >
-        </p>
-        <p>
-          The <code>/search</code> path is currently broken. This will
-          addressed soon.
-        </p>
-        <p>
-          This domain previously hosted CC Search, which became
-          <a href="https://openverse.org/?referrer=creativecommons.org"
-            >Openverse</a
-          >.
-        </p>
+      <header>
+        <h1>404 Page Not Found</h1>
+      </header>
+
+      <div class="content">
+        <p>We're sorry, your request could not be found.</p>
+        <a href="/">Return Home</a>
       </div>
     </main>