CSS Grid is a powerful layout system in web design that allows developers to create complex and responsive web layouts easily. It works by dividing a webpage into rows and columns, enabling designers to place elements precisely where they want them. This flexibility makes it simple to adapt designs for different screen sizes, ensuring a consistent look across devices. With CSS Grid, you can control the size and position of items using a grid template. This means you can create layouts that are both visually appealing and functional, without relying on floats or positioning tricks. Overall, CSS Grid simplifies the process of building modern web interfaces.