I found the following description in the enlightening “What’s New” PDF included with QuarkXPress 8. Check it out:
The Design Grid feature is an extension of the baseline grid feature in earlier versions of QuarkXPress. In earlier versions of QuarkXPress, you had just one baseline grid for an entire layout. In QuarkXPress 8, you can define different baseline grids for different master pages, and even apply a baseline grid to a text box.
In addition to controlling the color of the baseline, you can define distinct colors and patterns for the topline, centerline, and bottomline — all of which can be positioned based on font size and line spacing (the distance from the topline to the bottomline is equal to a font’s em height). When a design grid is displayed, you can align text visually, lock text to the grid, and even snap items to the grid.
Design Grid gridlines
In addition to creating design grids that are specific to master pages and text boxes, you can create Grid Styles that work like style sheets and item styles. You can even link a grid style to a style sheet — so that if the style sheet changes, the grid changes too.
Here’s where you access all that gridalicious grooviness: choose Edit> Grid Styles… The dialog box that appears looks like every other “style”-related dialog in QuarkXPress:
But when you click the Edit or New buttons, the fun begins. You can define how the text aligns:
and how its gridlines look:
Jay Nelson is the editorial director of PlanetQuark.com, and the editor and publisher of Design Tools Monthly. He’s also the author of the QuarkXPress 8 and QuarkXPress 7 training titles at Lynda.com, as well as the training videos Quark includes in the box with QuarkXPress 7 . In addition, Jay writes regularly for Macworld and Photoshop User magazines and speaks at industry events.