Understanding grid-template-rows and grid-template-columns

To begin mastering CSS Grid layouts, you need to understand how to define the structure of your grid using the grid-template-rows and grid-template-columns properties. These properties allow you to specify the number and size of the rows and columns in your grid container.

The syntax for both properties is straightforward: provide a space-separated list of track sizes using units such as px, em, %, fr (fractional units), or keywords like auto.

Example:

• grid-template-columns: 200px 1fr 2fr; creates three columns:
  • First column fixed at 200 pixels;
  • Second column takes up one fraction of the remaining space;
  • Third column takes up two fractions of the remaining space.
• grid-template-rows: 100px auto; creates two rows:
  • First row fixed at 100 pixels;
  • Second row automatically adjusts to fit its content.

Best Practices:

• Use flexible units like fr for responsive layouts;
• Keep grid definitions clear and readable;
• Avoid overly complex track listings unless necessary for your design.

How Changing Grid Definitions Affects Layout

When you adjust the values of grid-template-rows and grid-template-columns, you directly control the number of tracks and their sizing, which in turn affects how grid items are displayed.

• Increasing the number of columns causes grid items to flow into additional vertical tracks;
• Changing a row's size expands or contracts the space available to its items;
• Using flexible units like fr allows your layout to adapt smoothly to different screen sizes;
• Fixed units such as px ensure precise control over track dimensions.

Understanding how these definitions interact helps you predict and manage the placement and sizing of grid items, making your layouts both robust and responsive.