Merge pull request #5671 from ncornette/master

Fix blank slides issue in Reveal slideshow pdf export

IPython/nbconvert/templates/html/slides_reveal.tpl

@@ -55,9 +55,16 b''
 <!-- For syntax highlighting -->
 <link rel="stylesheet" href="{{resources.reveal.url_prefix}}/lib/css/zenburn.css">
 
-<!-- If the query includes 'print-pdf', use the PDF print sheet -->
+<!-- If the query includes 'print-pdf', include the PDF print sheet -->
 <script>
-document.write( '<link rel="stylesheet" href="{{resources.reveal.url_prefix}}/css/print/' + ( window.location.search.match( /print-pdf/gi ) ? 'pdf' : 'paper' ) + '.css" type="text/css" media="print">' );
+if( window.location.search.match( /print-pdf/gi ) ) {
+        var link = document.createElement( 'link' );
+        link.rel = 'stylesheet';
+        link.type = 'text/css';
+        link.href = '{{resources.reveal.url_prefix}}/css/print/pdf.css';
+        document.getElementsByTagName( 'head' )[0].appendChild( link );
+}
+
 </script>
 
 <!--[if lt IE 9]>