text: var chart = c3.generate({
      data: {
          columns: [
              ['sample', 30, 200, 100, 400, 150, 250]
          ]
      },
      axis: {
          y: {
              max: 400,
              min: -400,
              // Range includes padding, set 0 if no padding needed
              // padding: {top:0, bottom:0}
          }
      }
  });
  