Understanding CSS Grid Layout: Basics, Terminologies, and Properties
CSS Grid Layout is a powerful two-dimensional layout system introduced by CSS to make designing web pages simpler and more flexible. Unlike traditional CSS layout methods such as floats and positioning, CSS Grid provides a more structured approach to arranging content on both the horizontal and vertical axes simultaneously. It allows web designers and developers to create complex layouts with less code and more control. In this blog post, we’ll explore the basics of CSS Grid, key terminologies, and the properties you need to understand to make full use of this layout system.
Introduction to CSS Grid Layout
The CSS Grid Layout system allows developers to create complex, flexible grid-based designs with just a few lines of CSS code. It provides an intuitive way of dividing the page into rows and columns, enabling the creation of sophisticated, responsive layouts. Unlike Flexbox, which is more suitable for one-dimensional layouts (either rows or columns), CSS Grid is a two-dimensional system that works on both rows and columns simultaneously. This makes it an excellent choice for creating web pages with complex layouts, like magazine-style designs or dashboards.
Since its introduction in CSS3, CSS Grid has become one of the most powerful tools in web design, making it possible to build responsive, flexible, and maintainable designs with minimal effort.
Key Terminologies in CSS Grid
To fully understand CSS Grid, it’s important to familiarize yourself with some key terminologies. These terms define the components that make up a grid layout and how you interact with them.
Grid Container
The grid container is the element that holds all the grid items. This is the element where you apply the display: grid or display: inline-grid property, turning it into a grid. Once an element becomes a grid container, its direct child elements automatically become grid items.
.container {
display: grid;
}
Grid Items
Grid items are the direct child elements of the grid container. These items are placed within the grid structure, and their position is controlled using various grid properties such as grid-column and grid-row.
<div class="container"> <div class="item">Item 1</div> <div class="item">Item 2</div> <div class="item">Item 3</div> </div>
Grid Lines
Grid lines are the lines that divide the grid into rows and columns. They are numbered starting from 1 and can be referenced to position grid items. There are both horizontal and vertical grid lines.
Grid Tracks
Grid tracks refer to the space between two grid lines. In other words, a track is the area that spans between two adjacent grid lines, forming a row or column. The width of the tracks can be defined using length units or fractional units (fr).
Grid Cells
A grid cell is the space between two horizontal and two vertical grid lines. Each grid cell can hold a single grid item, and the size of the cell is determined by the size of the grid tracks.
Grid Areas
A grid area is a rectangular space within the grid made up of one or more grid cells. Grid items can span across multiple grid cells, forming a grid area. Grid areas are named using the grid-template-areas property, making it easier to manage complex layouts.
Basic Structure of CSS Grid Layout
The basic structure of CSS Grid revolves around defining a grid container, specifying grid tracks, and placing grid items into these tracks. Here’s a simple example to illustrate the layout:
<div class="grid-container"> <div class="grid-item">1</div> <div class="grid-item">2</div> <div class="grid-item">3</div> <div class="grid-item">4</div> <div class="grid-item">5</div> <div class="grid-item">6</div> </div>
In this example, we created a grid with 3 rows and 3 columns, with a gap of 10px between the grid items. Each grid item takes up one cell within the grid. The grid-template-columns and grid-template-rows properties define the size of the columns and rows, respectively.
CSS Grid Properties for the Container
The grid container has several properties that define how the grid is structured and how the grid items are positioned.
display: grid and display: inline-grid
The display property is used to turn an element into a grid container. The display: grid value turns the container into a block-level grid, while display: inline-grid makes the grid an inline element, which can flow within text content.
.container {
display: grid;
}
grid-template-rows and grid-template-columns
These properties define the number and size of the rows and columns in the grid. You can use fixed units (px, em, etc.), percentages, or fractional units (fr).
.container {
grid-template-columns: 1fr 2fr 1fr; /* Three columns with different widths */
grid-template-rows: 100px auto; /* Two rows, fixed height and auto height */
}
grid-template-areas
The grid-template-areas property allows you to define grid items more visually by naming the areas of the grid. This makes it easy to position items by referencing their respective areas.
.container {
grid-template-areas: "header header header"
"main content content"
"footer footer footer";
}
gap
The gap property sets the space between rows and columns. You can also use row-gap and column-gap to specify gaps between rows and columns separately.
.container {
gap: 20px;
}
CSS Grid Properties for Grid Items
Once the grid container is defined, you can control the positioning of individual grid items using a set of grid-specific properties.
grid-row and grid-column
The grid-row and grid-column properties allow you to specify where a grid item should start and end on the respective axes. These properties accept a pair of values that define the starting and ending lines for the item.
.item {
grid-row: 1 / 3; /* Start at line 1 and end at line 3 */
grid-column: 2 / 4; /* Start at line 2 and end at line 4 */
}
grid-area
The grid-area property is a shorthand for specifying the position of an item in both the row and column axes. It can also be used with grid-template-areas to reference named grid areas.
.item {
grid-area: main; /* Refers to a named grid area */
}
justify-self and align-self
These properties allow you to control the alignment of individual grid items along the horizontal (justify) and vertical (align) axes.
.item {
justify-self: center; /* Aligns the item horizontally in the center */
align-self: end; /* Aligns the item vertically at the end */
}
Advanced Grid Layout Techniques
Once you’re comfortable with the basics, you can explore some advanced techniques to take full advantage of CSS Grid.
Implicit vs. Explicit Grid
The explicit grid is the grid you define using grid-template-rows, grid-template-columns, and grid-template-areas. If there are more grid items than defined in the explicit grid, CSS Grid creates an implicit grid, where the grid items are automatically placed in the new rows or columns.
Fractional Units (fr)
The fr unit is one of the most powerful aspects of CSS Grid. It represents a fraction of the available space in the grid container. The fr unit allows for flexible layouts where the columns and rows share space dynamically.
.container {
grid-template-columns: 1fr 2fr; /* The second column will take twice as much space as the first */
}
Auto-placement
CSS Grid has an auto-placement feature that automatically places grid items in the next available grid cell. You can control this behavior with grid-auto-rows and grid-auto-columns properties.
Real-World Examples and Use Cases
CSS Grid is incredibly versatile and can be used to create a wide range of layouts. A few examples of real-world use cases include:
- Magazine-style layouts with multiple content blocks
- Dashboards with complex grid-based arrangements of widgets
- Photo galleries with responsive image grids
- Forms with custom layouts of input fields and labels
By combining Grid with Flexbox and other CSS properties, you can create highly responsive and adaptable layouts.
Conclusion
CSS Grid Layout has transformed the way we build web page layouts. By allowing designers to create flexible and responsive grid structures, CSS Grid significantly reduces the complexity and amount of code required for complex layouts. Understanding the basic properties and terminologies of CSS Grid will help you unlock its full potential and enable you to create sophisticated layouts with ease. Whether you’re building a simple webpage or a complex web application, mastering CSS Grid is an essential skill for modern web design.
FREQUENTLY ASKED QUESTIONS [FAQs]
1. What is CSS Grid Layout?
CSS Grid Layout is a two-dimensional layout system in CSS that enables designers to create complex layouts with both rows and columns. It allows for precise control over placement, alignment, and responsiveness without relying on floats or positioning.
2. What are grid lines in CSS Grid?
Grid lines are the horizontal and vertical lines that divide a grid into rows and columns. They serve as references for placing grid items. You can refer to these lines when positioning items using properties like grid-column and grid-row.
3. What is a grid container in CSS Grid?
A grid container is the element that holds all the grid items. To create a grid container, you need to set display: grid (or display: inline-grid) on the element. Its direct child elements automatically become grid items.
4. What are grid items?
Grid items are the direct child elements of a grid container. They are automatically placed inside the grid, and their position is controlled through properties like grid column, grid-row, and grid area. Each grid item occupies one or more grid cells.
5. What is the difference between grid-template-columns and grid-template-rows?
grid-template-columns define the size of columns in the grid, while grid-template-rows sets the height of the rows. Both properties accept lengths, percentages, and fractional units (fr) to create flexible and responsive grids.
6. How does the grid-template-areas property work?
The grid-template-areas property allows you to visually define grid items by naming grid areas. It uses a string to represent the layout, where each item is assigned a name. This simplifies positioning grid items based on their assigned areas.
7. What is the gap property in the CSS Grid?
The gap property (also known as grid gap) defines the spacing between rows and columns in a grid. You can set a uniform gap for both rows and columns or use row-gap and column-gap for different spacing between them.
8. What is the purpose of fractional units (fr) in CSS Grid?
The fr unit is a flexible unit that represents a fraction of the available space in the grid container. It allows for dynamic resizing of columns and rows, making it easy to distribute space evenly or proportionally within the grid.
9. What is the difference between display: grid and display: inline grid?
display: grid creates a block-level grid container, meaning it occupies the full width of its parent. On the other hand, display: inline-grid creates an inline-level grid container, allowing it to flow within inline content, similar to how inline elements behave.
10. How can grid items span multiple rows or columns?
You can use the grid-column and grid-row properties to specify where a grid item should start and end along the horizontal and vertical axes. This allows items to span across multiple rows or columns, creating more complex layouts within the grid.
