fix expand and tabs shortcodes to work with strict Content-Security-Policy

When the Content-Security-Policy header has "style-src 'self';"
inine style elements like style="display: none" are not honored
by browsers, so add CSS to the markup classes and style them
display: none

assets/_shortcodes.scss

@@ -31,6 +31,10 @@
     padding: $padding-16;
   }
 
+  .book-expand-expander {
+    display: none;
+  }
+
   input[type="checkbox"]:checked + .book-expand-content {
     display: block;
   }
@@ -56,6 +60,10 @@
     cursor: pointer;
   }
 
+  .book-tabs-radio {
+    display: none;
+  }
+
   .book-tabs-content {
     order: 999; //Move content blocks to the end
     width: 100%;