In my last Responsive Web Design article, we went over media queries. This is an important aspect to know of Responsive Web Design (RWD from now on) because it is this CSS declaration that allows for the different layouts to appear at different screen sizes.
Hmm, now what about different screen sizes? For easier understanding, lets look at this using an analogy. So, imagine that RWD is a blueprint for a wonderfully new house. The foundation, which the rest of the house depends on, would be media queries. After the foundation comes the first level of the house, which sets the tone for how the rest of the house will be built. In this house, the first floor would be break points.