Responsive Web Design
Responsive Web Design is one of the Industry catch phrases of the last few years. It represents a natural response to changing technology.
If you think of publishing a book, you make a decision as to the format, the type face, the size of print, the paper you print it on, hard cover or paperback and the like. Essentially you have control over the medium that presents the information contained in the book.
Websites are different, there are all manner of devices that may be used to show the content of the page, from and full HD TV Monitor, a Desk Top PC, all manner of laptop screens in all manner of sizes and formats, Tablets and I-pads that get turned portrait and landscape at whim, and of course the ever present mobile phone.
Responsive Webdesign simply reflect the technology that builds into the theme of the website that means based on the device being used the content will adapt to that device.
Most contemporary design will be Responsive, however if you site was designed some time back that may be a problem. Given that 60% of web visits these days are from mobile devices it is a non-negotiable for modern design practice, and if your site does not adapt, then it is time to talk to a web developer.