If you’re serious about responsive web design, you will need to continually test your layout as you work through code. I recently found a great online tool that let’s you do just that.
Not that many years ago, we were using tables for layout in our designs. This was the best option we had for forcing elements to be in specific positions on the page. Of course, now we wouldn’t dream of using tables for layout in our designs. Tables are terrible and we chastise ourselves for even thinking they were good … right?