<h1 class="firstsection">Section One Heading</h1>
<h1 class="secondsection">Section Two Heading</h1>
<h1 class="thirdsection">Section Three Heading</h1>

Could be style by:

<style type="text/css">
h1.firstsection  {font-size: 12pt; color: red;font-weight:bold}
h1.secondsection {font-size: 16pt; color: green;font-weight:normal}
h1.thirdsection  {font-size: 20pt; color: blue;font-weight:bold}
</style>

         

This would look like: