Responsive ‘mobile-friendly’ website
Bootstrap. Designed for everyone, everywhere.
Bootstrap’ grid system is responsive, and the columns will re-arrange depending on the screen size: On a big screen it might look better with the content organized in three columns, but on a small screen it would be better if the content items where stacked on top of each other.
Bootstrap is the most popular HTML, CSS, and JavaScript framework for developing responsive, mobile-first web sites. Bootstrap is completely free to download and use!