Why does the print on Facebook become smaller without warning? Is it my computer? Is it me ?

[Spell]

This has happened to me in the past. I have windows 8, not accustomed to it yet. And Safari browser. I was writing a note and the print just became smaller, lots smaller. I couldn't fix it..maybe I clicked on something, or whatever, but I don't know how to fix this. Emails seems to be OK on other sites, it's the Facebook I was on when it happened and all of Facebook, not just the note, is still in small print

[Daniel]

Ctrl+Scroll Wheel will adjust the zoom of the webpage

Ctrl++ and Ctrl+- will also adjust the zoom (So Ctrl and + or Ctrl and -)

You likely pressed control and slid your hand on the scroll wheel accidentally.