Fix line wrap for code/pre blocks

themes/custom/static/css/pygment.css

@@ -1,3 +1,19 @@
+code {
+  overflow: auto;
+  /*
+   * This uses `white-space: pre-wrap` to get elements within <pre> tags to wrap.
+   * Python, for code chunks within three backticks (```), doesn't wordwrap code lines by default,
+   * because they're within <pre> tags, which don't wrap by default.
+   * See https://github.com/github/markup/issues/168 , which is specifically about this parsing issue,
+   * even though that link's discussion is talking about GitHub.
+   */
+  white-space: pre-wrap; /* css-3 */
+  white-space: -moz-pre-wrap; /* Mozilla, since 1999 */
+  white-space: -pre-wrap; /* Opera 4-6 */
+  white-space: -o-pre-wrap; /* Opera 7 */
+  word-wrap: break-word; /* Internet Explorer 5.5+ */
+}
+
 td.linenos .normal {
   color: inherit;
   background-color: transparent;