Add subscribe form to second edition index page

blog/static/css/main.css

@@ -54,6 +54,10 @@ main img {
   border: 2px solid #999;
 }
 
+.posts.subscribe {
+  border: 2px solid #aaa;
+}
+
 .posts.bare-bones {
   border: 2px solid #66f;
 }
@@ -248,3 +252,25 @@ div.warning {
   border-radius: 5px;
   background-color: #ffa50022;
 }
+
+form.subscribe {
+  margin: 1rem;
+}
+
+div.subscribe-fields {
+  display: flex;
+}
+
+form.subscribe input {
+  padding: .5rem;
+  border: 1px solid #e5e5e5;
+}
+
+form.subscribe input[type=email] {
+  flex: 1;
+}
+
+form.subscribe input[type=submit] {
+  padding: .25rem .5rem;
+  cursor: pointer;
+}