Golden Grid System (GGS) splits the screen into 18 even columns. The leftmost and rightmost columns are used as the outer margins of the grid, which leaves 16 columns for use in design.
Now, 16 columns sounds a bit much for anything other than huge widescreen monitors. This is where the folding, inspired by the DIN paper system and Unigrid, comes in. The 16 columns can be combined, or folded, into 8 columns for tablet-sized screens, and into 4 columns for mobile-sized ones. This way GGS can easily cover any screen sizes from 240 up to 2560 pixels.
While the column widths in GGS are proportional to the screen’s width, the widths of its gutters (the spaces between columns) are proportional to the page’s font-size, specified in ems.
Responsive grids that use gutters proportional to the screen can make the content feel like it’s being squeezed together or pulled apart as the screen width changes. With elastic gutters this just doesn’t happen, as the gutters always stay in proportion to the content.