Region

# region.js

var chart = c3.generate({ data: { columns: [ ['data1', 30, 200, 100, 400, 150, 250, 400], ['data2', 830, 1200, 1100, 1400, 1150, 1250, 1500], ], axes: { data2: 'y2' } }, axis: { y2: { show: true } }, regions: [ {axis: 'x', end: 1, class: 'regionX'}, {axis: 'x', start: 2, end: 4, class: 'regionX'}, {axis: 'x', start: 5, class: 'regionX'}, {axis: 'y', end: 50, class: 'regionY'}, {axis: 'y', start: 80, end: 140, class: 'regionY'}, {axis: 'y', start: 400, class: 'regionY'}, {axis: 'y2', end: 900, class: 'regionY2'}, {axis: 'y2', start: 1150, end: 1250, class: 'regionY2'}, {axis: 'y2', start: 1300, class: 'regionY2'}, ] });

# region.css

.c3-region.regionY {
  fill: red;
}
.c3-region.regionY2 {
  fill: green;
}