The 1Kb CSS Grid Framework
There are various CSS frameworks which offer a grid system, a style reset, basic typography, form styling & more.
But, if you only need a lightweight grid framework to build the skeleton of your website, take a look at the 1Kb CSS Grid.
It supports both fluid grids besides the fixed-width ones and nested rows can be created.
The website of the framework provides a generator to customize the grid & download the CSS easily.
Also, Usability Post has a very detailed introduction to the 1Kb CSS Grid in 3 steps. To dig the details, make sure you check them: