CSS Styles

Hi There

Trying to change the look of titles and text in my site origin widgets.
I am adding style attributes but these are not reflected in the page refresh.

–for example – i want to make my title smaller.
In the browser dev tools i can see it is a h3 with class widget-title..
so in the widget style attributes section i add h3.widget-title{font-size:18px;}
The new style does not take effect..
Please advise how i can change the style of the widget content using the attribute sidebar panel..

Also, according to the browser dev tools the existing styles are inline – so i cannot change them in styles.css

Many Thanks