Tune markdown CSS to increase readability

The default CSS is not very comfortable for markdown, as for example the
links are hidden.

This patch makes the markdown CSS tunable by wrapping it into a div, and
then adjusting the default styles to increase readability.

static/git-arr.css

@@ -225,3 +225,20 @@ span.ctrlchr {
     padding: 0 0.2ex 0 0.1ex;
     margin:  0 0.2ex 0 0.1ex;
 }
+
+/*
+ * Markdown overrides
+ */
+
+/* Colored links (same as explicit links above) */
+div.markdown a {
+    color: #038;
+}
+div.markdown a:hover, div.markdown a:active {
+    color: #880000;
+}
+
+/* Restrict max width for readability */
+div.markdown {
+    max-width: 55em;
+}

views/blob.html

@@ -73,7 +73,9 @@
 %   end
 </table>
 % elif can_markdown(repo, fname.unicode):
+<div class="markdown">
 {{!markdown_blob(blob.utf8_content)}}
+</div>
 % elif can_colorize(blob.utf8_content):
 {{!colorize_blob(fname.unicode, blob.utf8_content)}}
 % else: