The options for re-sizing text vary with the browser.  For all browsers, you may increase or decrease the text size by simultaneously pressing the following keys:

Re-sizing text option

Computer Type	Increase Text Size	Decrease Text Size
Windows PC	Control (Ctrl) and Plus (+)	Control (Ctrl) and Minus (-)
Macintosh	Command and Plus (+)	Command and Minus (-)

Note that the percent increase or decrease will vary with your browser as well as your current text size setting.

Other methods of controlling the text size vary with the browser.

Internet Explorer

Select View -> Text Size and then Largest, Larger, Medium, Smaller, or Smallest.
or
Select View -> Zoom and then select Zoom in or Zoom out or an explicit percent size.

Firefox

Select View -> Zoom and then Zoom In or Zoom Out.  Reset restores normal view.  

Note: If you select the option Zoom Text Only, the text may become too large for the space allotted on the page and overlap other areas, becoming illegible.

Chrome

Select 'Customize and control Google Chrome' (3 dots icon in the upper right corner) and then by "Zoom" select + (zoom in) or - (zoom out).

Safari

Select View and then Zoom In or Zoom Out.  Actual Size restores normal view.  

Note: If you select the option Zoom Text Only, the text may become too large for the space allotted on the page and overlap other areas, becoming illegible.