pixture_reloaded.css overrides the theme setting for H3 size within a block: line 582

.block h3 {
  padding: 0 3px;
  font-size: 1em;

Unfortunately rendering of a full node inserts the content into a div with a block class causing the H3 size to be overridden here as well.
<div id="content">
   <div id="block-system-main" class="block block-system no-title odd first last block-count-2 block-region-content block-main" >
     <div class="node-content">

I can override this again within my own css but it is clumsy and defeats the whole theme concept.