Further explanation for Step 3

[cslarson]

Not sure if this is the place to ask this, but was hoping someone might further explain the purpose of centering the grid horizontally. We're investigating the use of grid systems at our firm and appreciate the flexible nature that the frameless grid seems to offer, but are still working to wrap our heads around how we would use it. Does the frameless grid concept only make sense when a developer is also using a css preprocessor?

[escapedcat]

To do the calculations for the em-values a preprocessor is pretty much needed, yes. But COMPASS/Sass is doing a good job here.