CSS Grid is a two-dimensional layout system for webpages, allowing the creation of a flexible grid of rows and columns to define the structure of a webpage.

Learning CSS Grid can be a great way to improve your web development skills and create flexible and responsive layouts. Here are some steps you can follow to get started:

1. Read the CSS Grid Layout documentation: The W3C provides comprehensive documentation on CSS Grid Layout, including examples and interactive tutorials. Start by reading through the basic concepts and understanding the terminology used in CSS Grid.

2. Experiment with a simple grid: Use a simple HTML file and a CSS stylesheet to create a grid layout. Try different grid configurations to get a feel for how CSS Grid works.

3. Work on practice projects: Create small projects such as a two-column layout or a grid with multiple rows and columns. This will help you understand how to use the various CSS Grid properties and how to create complex layouts.

4. Learn about responsive design: CSS Grid can be used to create responsive designs that adjust to different screen sizes. Read up on responsive design and experiment with creating responsive grid layouts.

5. Join online communities: There are many online communities and forums where you can ask questions, share your projects, and learn from others who are also learning CSS Grid.

6. Keep practicing: Keep experimenting and working on small projects to continually improve your CSS Grid skills. The more you practice, the more comfortable you will become with using CSS Grid in your projects.

   The most common use case of CSS Grid is for creating layouts for websites and web applications, such as grids for arranging items in a header, footer, sidebar, and main content area. It is particularly useful for creating responsive designs that adjust to different screen sizes and devices.

.container {
  display: grid;
  width: 750px;
  height: 600px;
  grid-template-columns: 200px 1fr 1fr;
  grid-template-rows: 80px 1fr 1fr 100px;
  grid-gap: 1rem;
  grid-template-areas:
      "header header header"
      "sidebar content-1 content-1"
      "sidebar content-2 content-3"
      "footer footer footer";
}

As we can see in the above example, CSS Grid Layout allows you to define grid areas using the grid-template-areas property. This property allows you to specify named grid areas in a grid layout, and then place individual grid items into those areas.

CSS Grid is also responsive, meaning that you can create grids that automatically adjust to different screen sizes.

This makes it easy to create complex layouts for desktop and mobile devices, without using hacks or workarounds.

Check out this amazing Codepen example by Katherine Kato:

In CSS Grid Layout, the "fr" unit (fractional unit) is a proportional unit that represents a fraction of the available space in the grid container.

For example, if a grid container has three columns with the declaration grid-template-columns: 1fr 1fr 1fr, it means that the three columns will have equal widths and each column will take up one-third of the available width in the grid container.

Similarly, if a grid container has three rows with the declaration grid-template-rows: 1fr 1fr 1fr, it means that the three rows will have equal heights and each row will take up one-third of the available height in the grid container.