How to change font size of axis titles in Apex charts?

[githubHemanth]

I have tried changing axis title font size using below code but it does not change font size.
`
yaxis: {

labels: {
        formatter: function (value) {
          return "$" + value;
        }           
        },
title: {
        text: 'Estimated Value',
        style:{
             fontSize: '28px'
              } 
       }
    }`

is there any other method to change font size for axis titles in Apex charts ?