Show translation diff for admins

app/assets/javascripts/mathjax-config.js

@@ -3,7 +3,8 @@ window.MathJax = {
     tex2jax: {
         inlineMath: [ ["$","$"], ["\\(","\\)"] ],
         displayMath: [ ["$$","$$"], ["\\[","\\]"] ],
-        processEscapes: true
+        processEscapes: true,
+        ignoreClass: "mathjax_ignore|diff"
     },
     "HTML-CSS": { availableFonts: ["TeX"] }
 };

app/assets/stylesheets/application.css.scss

@@ -55,6 +55,33 @@ body {
   margin: 20px -30px 0;
 }
 
+/* Style for translation diffs */
+
+.diff {
+  overflow:auto;
+  margin-bottom: 20px;
+  ul{background:#fff;overflow:auto;font-size:13px;list-style:none;margin:0;padding:0;display:table;width:100%;}
+  del, ins{display:block;text-decoration:none;}
+  li {
+    padding:0;
+    display:table-row;
+    margin: 0;
+    height:1em;
+    ins {
+      background:#dfd;
+      color:#080;
+      strong{font-weight:normal;background:#9f9;}
+    }
+    del {
+      background:#fee;
+      color:#b00;
+      strong{font-weight:normal;background:#fcc;}
+    }
+    /* try 'whitespace:pre;' if you don't want lines to wrap */
+    del, ins, span {white-space:pre-wrap;font-family:courier;}
+  }
+}
+
 /* Custom css for fixing styles within problem content */
 
 .problem-content {