When using Google Fonts with WordPress, you should NOT use @import, nor just place the HTML in the header. Instead use a function and enqueue them.
When WordPress 3.5 beta 1 was released it came with, “Twenty Twelve”. While looking at style.css, I noticed the use of “REM” to set font sizes and margins. I had NO idea what REM was. In fact, I just started using EM’s in other child themes. Immediately, I turned to Google and started researching.