Adds a raw string to the builder that will be concatenated with the next class or value added to the builder. This method is generally used internally by CssBuilder to append content directly to the internal string buffer.

public CssBuilder AddValue(string value)

ClassToRender = new CssBuilder("my-base")
                        .AddValue("-suffix")
                        .Build();

// ClassToRender: "my-base-suffix"