A grid system is a defined set of vertical columns and optionally horizontal rows based on time-tested principles of graphic design and layout. Ensuring a consistent grid system within your application and across all Astro applications creates a sense of continuity and relationship from screen to screen and app to app, even when the layouts between those screens may have dramatically different requirements.

Columns, Gutters and Margins

The Astro Grid is a standard 12 column grid with column widths that expand or contract in relation to the width of the display. Columns are separated by a fixed-width gutter. Astro-compliant applications may use gutters of either 20 pixels (default) or 10 pixels (compact). The grid is enclosed by a fixed-width margin of 30 pixels.

Sample grid 20px gutter.
Sample grid 20px gutter.
Sample grid 10px gutter.
Sample grid 10px gutter.


At certain screen sizes, Astro optimizes for display on narrow devices by reducing the number of columns and rearranging the layout of your application via responsive design practices.

Breakpoint Columns Margin Cap Gap (compact)
0-350px 4 20px 20px 10px
351-768px 8 30px 20px 10px
769px 12 30px 20px 10px

CSS Grid is the recommended method for implementing a grid in your Astro project. Using a custom layout grid adds overhead and layers of incompatibility, and as such, should only be used if your project requires backwards-compatibility with Internet Explorer 9 or earlier.