MDL-47494 ddwtos: NOBUG css to fix alignment when superscripts and subscripts in drag boxes

Fixes weird layout bug with web browsers that means the boxes will not line up.

question/type/ddwtos/README.txt

@@ -15,30 +15,9 @@ This question type is compatible with Moodle 2.1+.
 
 To install using git, type this command in the root of your Moodle install
     git clone git://github.com/timhunt/moodle-qtype_ddwtos.git question/type/ddwtos
-Then add question/type/ddwtosto your git ignore.
+Then add question/type/ddwtos to your git ignore.
 
 Alternatively, download the zip from
     https://github.com/timhunt/moodle-qtype_ddwtos/zipball/master
 unzip it into the question/type folder, and then rename the new folder to
 ddwtos.
-
-
-Note that, if you put superscripts and subscripts in your drag boxes, then there
-is a weird layout bug with web browsers that means the boxes will not line up.
-You can solve this by putting something like this in your theme CSS:
-/*
- * Superscript and subscript: don't use default styling, it does weird things to
- * line height. This fix comes from https://github.com/necolas/normalize.css
- */
-sub,
-sup {
-    font-size: 80%;
-    position: relative;
-    vertical-align: baseline;
-}
-sup {
-    top: -0.4em;
-}
-sub {
-    bottom: -0.2em;
-}

question/type/ddwtos/styles.css

@@ -80,3 +80,16 @@
 .que.ddwtos .group8 {
     background-color: #F0E68C;
 }
+
+.que.ddwtos sub,
+.que.ddwtos sup {
+    font-size: 80%;
+    position: relative;
+    vertical-align: baseline;
+}
+.que.ddwtos sup {
+    top: -0.4em;
+}
+.que.ddwtos sub {
+    bottom: -0.2em;
+}