Here is the stacked chart I have, I would like to be able to change the color of the session (here red) in transparent. Would you have an idea ? thanks.
And here is my code :
var data = google.visualization.arrayToDataTable(my_data);
var options = {
title: 'S-Score',
colors: ['red', '#70a1c0'],
width: 700,
height: 400,
chartArea: { width: "60%" },
fontSize: 14,
legend: { position: 'right' },
bar: { groupWidth: '75%' },
isStacked: true
};
var chart = new google.visualization.ColumnChart(document.getElementById('E_chart'));