Cant Change color or fonts

Ok, so I have spent so much time on this problem 🙁
I have tried everything from creating child themes, to adding plugin that help customize themes….I cannot seem to change the font & colors I need for this theme.
I don’t know a lot about CSS but I downloaded the CSS Manager plugin and this is what I added but got no results or changes whatsoever what am I doing wrong? How can I change the style of things on this theme? I might just choose another theme, but I love this one so much.
Thank you for the help!

/*73*/
.site-title {
font-size: 45px;
color: #c74180;
}
/*102*/
.entry-title, .page-title {
color: #ec5f99;
}
/*169*/
.widget-title em {
font-size: 28px;
color: #e34e9d;
}
/*174*/
.widget ul.menu li {
color: #711856;
}