This is a CSS grid system for designing adaptive websites. It contains 4 layouts and 3 sets of typography presets, all based on a single grid.
The goal of Less Framework is to make building websites with multiple layouts efficient, and to make the layouts feel consistent. Since every layout is based on the same grid, elements used in one layout can often be reused in the others without changing them much at all. For example, simply adjusting the width or font-size of an element in one layout is often enough to make it work in another. And even if more changes are required, the common baseline grid and type presets will make the element fit in.
Less Framework is simple. It does not contain any predefined column classes, pre-compilers, or other wizardry. The point of it is to let everyone keep writing HTML and CSS as they always have, because everyone does it differently.
Solid knowledge of HTML and CSS is recommended. You'll find the dimensions for each layout noted down in comments within the CSS files.