In graphic design, a grid is a structure made up of a series of vertical and horizontal lines used to structure content.A grid is widely used to design layout and content structure in print design.In web design, a grid is a very effective method to create a consistent layout rapidly and effectively using HTML and CSS.
Bootstrap provides a responsive, mobile-first fluid 12-column grid system.The responsive grid system appropriately scales up to 12 columns as the device or viewport size increases.