[qsrc2tw] Style the `h2` and `img` slightly prettier.

qsrc2tw/twine-code/style/style.css

@@ -1,8 +1,15 @@
 h2{
-    text-align: center;
-    color: maroon;
+	text-align: center;
+	font-size: 2em;
+	margin: 0;
 }
 
 #passages{
-    padding: 0.5em 2em;
+	padding: 0.5em 2em;
+}
+
+.passage>img {
+	margin-left: auto;
+	margin-right: auto;
+	display: block;
 }