How to increase the line thickness in chart?

How to increase the line thickness in chart? I using rrd4j for storing data and default chart -n3 line chart from openHab in Habpanel. Every works great, but line in chart is so thin.
I use openhab version 2.3.0.

I am afraid but you can’t adjust the charts… Yet… Looking for a dev for this.
You can use influxdb and grafana to get great looking graphs