how to change h1-h6 in my twentysixteen-child theme?

Here is what I have for my entry title and blog tile (still have to figure out how to load Google fonts). But how do I change h tags?
.entry-title {
font-family: “Poppins”, sans-serif;
font-weight: 400;
font-size: 30px;
font-size: 1.875rem;
line-height: 1.225;
margin-bottom: 1.05em;
}

.site-title {
font-family: “Poppins”, sans-serif;
font-size: 23px;
font-size: 1.4375rem;
font-weight: 400;
line-height: 1.2173913043;
margin: 0;
}

Currently my h2 tags are bigger than my titles.
https://blog.christopherrichards.com/2016/04/28/slow-get-smart/