:Add HN self link

Uses "HN" instead of the "Y" in the YCombinator icon.

* style.css: Create HN icon out of link.
* tpl/.config: Add HN link.

style.css

@@ -296,6 +296,32 @@ body.index footer hr,
   text-decoration: none;
 }
 
+.hn-icon {
+    display: block;
+
+    /* note that border won't be visible on default
+       white page background */
+    background-color: #ff6600;
+    border: 1px solid white;
+
+    /* 1px border = 42x42 */
+    width: 40px;
+    height: 40px;
+
+    font-size: 16px;
+    font-weight: bold;
+    text-align: center;
+    line-height: 40px;
+}
+
+.hn-icon,
+a.hn-icon:visited,
+a.hn-icon:active,
+a.hn-icon:hover {
+    color: white;
+    text-decoration: none;
+}
+
 .bimgs {
   float: right;
   margin-left: 1em;

tpl/.config

@@ -145,6 +145,10 @@ html_index_footer=$(cat <<EOM
         width="42" height="42" border="0"
         />
     </a>
+
+    <a href="https://news.ycombinator.com/user?id=mikegerwitz"
+       title="mikegerwitz on Hacker News"
+       class="hn-icon">HN</a>
   </div>
 EOM
 )