CSS Grid Layout

Grid Layout

CSS Grid Layout, simply known as Grid, is a layout scheme that is the newest and the most powerful in CSS. It is supported by all major browsers and provides a way to position items on the page and move them around.

It can automatically assign items to areas, size and resize them, take care of creating columns and rows based on a pattern you define, and doing all the calculations using the newly introduced fr unit.

Why Grid?

• You can easily have a 12-column grid with one line of CSS. grid-template-columns: repeat(12, 1fr)
• Grid lets you move things in any direction. Unlike Flex, where you can move items either horizontally (flex-direction: row) or vertically (flex-direction: column) - not both at the same time, Grid lets you move any grid item to any predefined grid area on the page. The items you move do not have to be adjacent.
• With CSS Grid, you can change the order of HTML elements using only CSS. Move something from top to the right, move elements that were in footer to the sidebar etc. Instead of moving the <div> from <footer> to <aside> in the HTML, you can just change it’s placement with grid-area in the CSS stylesheet.

Grid vs. Flex

• Flex is one-dimensional - either horizontal or vertical, while Grid is two-dimensional, meaning you can move elements in both horizontal and vertical planes
• In Grid, we apply layout styles to the parent container and not the items. Flex on the other hand targets the flex item to set properties like flex-basis, flex-grow, and flex-shrink
• Grid and Flex are not mutually exclusive. You can use both on the same project.

Checking browser compatibility with @supports

Ideally, when you build a site, you’d design it with Grid and use Flex as a fallback. You can find out if your browser supports grid with the @support CSS rule (aka feature query). Here’s an example:

.container {
  display: grid; /* display grid by default */
}

@supports not (display: grid) { /* if grid is not supported by the browser */
  .container {
    display: flex; /* display flex instead of grid */
  }
}

Getting Started

To make any element a grid, you need to assign its display property to grid, like so:

.conatiner {
  display: grid;
}

And that’s it. You just made your .container a grid. Every element inside the .container automatically becomes a grid item.

Defining templates

Rows and columns

grid-template-columns: 1fr 1fr 1fr 1fr;
grid-template-rows: auto 300px;

Areas

grid-template-areas: 
  "a a a a"
  "b c d e"
  "b c d e"
  "f f f f";

or

grid-template-areas:
  "header header header header"
  "nav main main sidebar";

Grid Areas

Here’s some sample code on how to define and assign grid areas

.site {
  display: grid;
  grid-template-areas: /* applied to grid container */
    "head head" /* you're assigning cells to areas by giving the cells an area name */
    "nav  main" /* how many values kind of depends on how many cells you have in the grid */
    "nav  foot";
}

.site > header {
  grid-area: head;
}

.site > nav {
  grid-area: nav;
}

.site > main {
    grid-area: main;
}

.site > footer {
    grid-area: foot;
}

The fr unit

Grid introduces a new fr unit, which stands for fraction. The good thing about using the fr unit is that it takes care of calculations for you. Using fr avoids margin and padding issues. With % and em etc. it becomes a math equation when calculating grid-gap. If you used fr unit, it’ll automatically calculate both column and gutter sizes and adjust the size of the columns accordingly, plus there will be no bleeding gaps at the end either.

Examples

Changing the order of elements based on screen size

Let’s say you want to move the footer to the bottom on small screens and to the right on bigger screens, and there’s a bunch of other HTML elements in between the two.

The simple solution is to change the grid-template-areas based on the screen size. You can also change the number of columns and rows based on the screen size, too. This is a much cleaner and simpler alternative to Bootstrap’s Grid system (col-xs-8 col-sm-6 col-md-4 col-lg-3).

.site {
  display: grid;
  grid-template-columns: 1fr 1fr;
  grid-template-areas:
    "title title"
    "main header"
    "main sidebar"
}

@media screen and (min-width: 34em) { /* If the screen is big enough, use a different template for grid areas */
  .site {
    grid-template-columns: 2fr 1fr 1fr;
    grid-template-areas:
      "title title title"
      "main header header"
      "main sidebar footer"
  }
}

See the Pen CSS Grid by example - 2 (grid areas + grid gap) by Aamnah Akram (@aamnah) on CodePen.