Desktop web browsers, tablets, and mobile devices are fundamentally different and are used in very different ways.
Agreed. But there are ways to make adaptive design but not apply so many rules.
A List Apart’s Ethan Marcotte on “Responsive Web Design”
Fluid grids, flexible images, and media queries are the three technical ingredients for responsive web design, but it also requires a different way of thinking. Rather than quarantining our content into disparate, device-specific experiences, we can use media queries to progressively enhance our work within different viewing contexts.