:sparkles: add copy-code-button plugin

book.json

@@ -26,7 +26,8 @@
         "search",
         "search-pro",
         "disqus",
-        "page-footer-ex"
+        "page-footer-ex",
+        "copy-code-button"
     ],
     "pluginsConfig": {
         "page-footer-ex": {

styles/website.css

@@ -16,3 +16,9 @@ li.chapter {
 .book-body {
     font-size: 1.5rem !important;
 }
+.copy-code-button {
+    display: none;
+}
+pre:hover > .copy-code-button {
+    display: block;
+}