I have never used pastebin before, so I hope this is correct.
<script src="http://pastebin.com/embed_js.php?i=2GhcUKm7"></script>
Perhaps I have set up the child theme incorrectly.
I have seen two different versions of what to do.
What I did, (and I think I found this in the codex) was duplicate the whole twenty twelve folder, and renamed it twentytwelve child. I created a new css file as per instructions with name etc and pointed it to the parent theme. This css file is in the same directory as the theme folders.
I just watched a tutorial on YouTube, and all they did was create an empty folder in which They put the new css file, with the same info that I have done.
This afternoon I added some items to my css file and it did not change the look of my site. So, I edited the css file within the child theme folder and that did the trick. So, i am a little confused!
Once I get over this initial hurdle I should be fine. I have worked with Joomla sites more recently and wordpress had changed a lot since I last used it. On te whole I think it looks a lot easier to work with.