Fixed width vs. variable width simply has to do with the way in which the width of the main text column changes when you change the width of the viewport (i.e., the browser window).
To easily see the difference, go to GreaterWrong.com, click on any post, and then look to the top right; you’ll see three small buttons, like this:
This is the width selector. Click on any of the three icons to select that width. The left-most button (‘normal’) and the middle button (‘wide’) are fixed-width layouts; the right-most button (‘fluid’) is a variable-width layout. Try resizing your browser window (changing its width) after selecting each of the options, and you’ll see what I am talking about.
Fixed width vs. variable width simply has to do with the way in which the width of the main text column changes when you change the width of the viewport (i.e., the browser window).
To easily see the difference, go to GreaterWrong.com, click on any post, and then look to the top right; you’ll see three small buttons, like this:
This is the width selector. Click on any of the three icons to select that width. The left-most button (‘normal’) and the middle button (‘wide’) are fixed-width layouts; the right-most button (‘fluid’) is a variable-width layout. Try resizing your browser window (changing its width) after selecting each of the options, and you’ll see what I am talking about.