A light weight 12 column vanilla CSS grid using floats. You can fork and customize as needed.
To use, include light-grid.css in your css folder. In your html page link to the file:
<link rel="stylesheet" href="css/light-grid.css">
Then include a wrapping element with a class of container. Inside container add an element with a class of row. Inside rows add as many elements with class of col-<number>. Column numbers fall between 1 and 12. The number of columns should only add up to maximum of 12.
The code below will create 2 rows, the first with 3 columns spanning 4 of the 12 grid, and a second row with 3 columns made up of two spanning 5 of 12 columns and one spanning 2 of 12.
<div class="container">
<div class="row">
<div class="col-4">4</div>
<div class="col-4">4</div>
<div class="col-4">4</div>
</div>
<div class="row">
<div class="col-5">5</div>
<div class="col-5">5</div>
<div class="col-2">2</div>
</div>
</div>
Here is a display image showing many possible combinations in the browser.
See a demo by loading index.html in a browser.