Added basic theming to the epub reader

cps/static/css/epub_themes.css

@@ -0,0 +1,14 @@
+.lightTheme {
+	background: #fff;
+	color: #000;
+}
+
+.darkTheme {
+	background: #000;
+	color: #fff
+}
+
+.sepiaTheme {
+	background: #ece1ca;
+	color: #000;
+}

cps/static/css/main.css

@@ -567,6 +567,31 @@ input:-moz-placeholder { color: #454545; }
   font-size: 0.8em;
 }
 
+.md-content .themes button {
+  display: inline-block;
+  border: none;
+  text-align: center;
+  text-decoration: none;
+  margin-top: 5%;
+  margin-right: 1%;
+  font-size: 16px;
+}
+
+.md-content .themes button.darkTheme {
+  background-color: black;
+  color: white;
+}
+
+.md-content .themes button.whiteTheme {
+  background-color: white;
+  color: black;
+}
+
+.md-content .themes button.sepiaTheme {
+  background-color: #ece1ca;
+  color: black;
+}
+
 /* Effect 1: Fade in and scale up */
 .md-effect-1 .md-content {
   -webkit-transform: scale(0.7);

cps/static/js/reading/epub.js

@@ -13,6 +13,10 @@ var reader;
         bookmarks: calibre.bookmark ? [calibre.bookmark] : []
     });
 
+    reader.rendition.themes.register("lightTheme", "/static/css/epub_themes.css");
+    reader.rendition.themes.register("darkTheme", "/static/css/epub_themes.css");
+    reader.rendition.themes.register("sepiaTheme", "/static/css/epub_themes.css");
+
     if (calibre.useBookmarks) {
         reader.on("reader:bookmarked", updateBookmark.bind(reader, "add"));
         reader.on("reader:unbookmarked", updateBookmark.bind(reader, "remove"));