That is called the tool button. Put your cursor on this and click. Another dialog box will open that should show the word zoom. Put the cursor on this and then another dialog box opens that will give you a variety of sizes in which to you the internet. We are set at 100%. Any other setting will result in a different way of seeing the screens. If you click on 100%, then any new screens that you look at will all be at 100%, not just this site. You can easily change back to the setting you current have by repeating this setting.