PMC (also known as PubMed Central) recently updated its look and feel, to conform to NCBI’s new standards for page design. This redesign allows for a cleaner and more uniform presentation across PMC’s site as well as its article, issue and journal archive pages.
For more information, see Fogelman M. What’s New in PMC: Another Facelift. NLM Tech Bull. 2012 Jul-Aug;(387):e4.