Change H1, H2, H3 Style

Hello. I’m a newbie without any coding or CSS experience.

I’m trying to make simple changes to the style for H1, H2, etc., but nothing seems to work. Below is the default style for headings in Unicon. If I change the font size in the style.css for H1, (for example from 36px to 42px), nothing changes on the blog. Am I missing something?

Thanks,
Scott

~~~~~~~~~~~~~~~~~~~
h1,
h2,
h3,
h4,
h5,
h6 {
font-family: Arial, Helvetica, sans-serif;
color: #444444;
font-weight: 400;
margin: 0 0 20px 0;
padding: 0;
line-height: 1.4;
}

h1 a,
h2 a,
h3 a,
h4 a,
h5 a,
h6 a { font-weight: inherit }

h1 {
font-size: 36px;
}

h2 {
font-size: 18px;
}

h3 {
font-size: 26px;
}

Ticket