Indicator styles are modified by an API and the reference for making such changes can be found here, within the Javascript API documentation on our developer site:
Below are examples of which aspects of the indicators can be manipulated by the API:
As you can see, each indicator has a variety of sizes that it will automatically switch to depending on the size of the widget boundaries in the dashboard, ranging from "big" to "small" (the main types) and "ticker".
Using JavaScript, an object of these configurations can be passed to the setOptions method on the indicatorInstance object within the widget "initialized" lifecycle hook:
widget.on('initialized', function(w) {
var options = {};
w.indicatorInstance.setOptions('numericBar', options);
});