Just a little info on this, this is not a charting library, it's probably closer to a graphics or visualization library.
It pulls a lot of it's ideas from d3.js, allowing CSS to dictate a lot of your style choices, but also allowing the data to change the style (a typical example is a chart where you have different categories of data, coloring those categories depending on the data).
This is low level for a reason, most charting libraries take a specific stance on how to visualize something. d3 and c2 let that be dictated entirely by the developer. It may take more effort to get a bar chart working in either of these libraries but generally the control you have allows you to fit it into your design rather than your design molding around the charting library you use.
It pulls a lot of it's ideas from d3.js, allowing CSS to dictate a lot of your style choices, but also allowing the data to change the style (a typical example is a chart where you have different categories of data, coloring those categories depending on the data).
This is low level for a reason, most charting libraries take a specific stance on how to visualize something. d3 and c2 let that be dictated entirely by the developer. It may take more effort to get a bar chart working in either of these libraries but generally the control you have allows you to fit it into your design rather than your design molding around the charting library you use.