CSS Flexbox has become an essential part of front-end web development due to its ability to efficiently align and organize elements inside a container. CSS Flexbox is responsive, allowing for the creation of flexible designs that can adapt to different screen sizes and devices. The flex-direction property allows developers to control the direction of the main axis, while the flex-wrap property enables items to wrap to the next line when required. The justify-content property aligns elements along the main axis, distributing leftover space equally among them. Additionally, the flex-grow and flex-shrink properties allow for the adjustment of item sizes based on available space. CSS Flexbox also offers a shorthand property called "flex" that combines these three properties into one line. With its flexibility and powerful features, CSS Flexbox has become a popular choice among web developers for creating responsive and visually appealing designs.