Slitherine

In typing a post I hit some key that changed the size of the font that I see on this board. It's only on this site so it's not my computer. What in the world did I do? How can I get the default font size back?

I found it. I'm using Firefox and it stores text size per site. I believed this happened when I held the Ctrl key while scrolling. Ctrl+0 restored it back to its normal size.