:email: Fix the Django News signup embed

The old embed URL, https://django-news.com/embed, now returns 404, so
the newsletter signup is already broken on the live site. Switch to
https://django-news.com?as_embed=true.

Cap the embed at the same 34rem as the webring below it, so neither one
spans the whole footer.

docs/stylesheets/django.css

@@ -77,9 +77,16 @@
   text-align: center;
 }
 
-.awesome-django-footer iframe {
-  max-width: 100%;
-  border: 0;
+/* Capped to match the webring below it, so neither spans the whole footer. */
+.awesome-django-newsletter {
+  margin: 0 auto;
+  max-width: 34rem;
+}
+
+.awesome-django-newsletter iframe {
+  width: 100%;
+  height: 220px;
+  border: 1px solid #ccc;
 }
 
 .awesome-django-footer p {

overrides/main.html

@@ -14,12 +14,13 @@
 {% block footer %}
   {{ super() }}
   <div class="awesome-django-footer">
-    <iframe
-      src="https://django-news.com/embed?color1=ffffff&color2=092e20&color_bg_button=092e20&color_border=ccc&color_button=ffffff&color_links=979797&color_terms=808080&title=Subscribe+to+Django+News"
-      width="450"
-      height="310"
-      loading="lazy"
-      title="Subscribe to Django News"></iframe>
+    <div class="awesome-django-newsletter">
+      <iframe
+        src="https://django-news.com?as_embed=true"
+        scrolling="no"
+        loading="lazy"
+        title="Subscribe to Django News"></iframe>
+    </div>
 
     <div class="awesome-django-webring">
       <webring-css site="https://awesomedjango.org"></webring-css>