In all themes except for the General Theme, we have a class called "heading", which can be used to style "h1" or "h2" tags. You can use it as follows:
<h1 class="heading">This is an "h1" tag.</h1>
<h2 class="heading">This is an "h2" tag.</h2>
In the General Theme, we use the "text-...". You can use it as follows:
<h1 class="text-red | text-green | text-yellow | text-blue | text-orange | text-grey | text-purple | text-center | text-right | text-left | text-justify">This is a heading.</h1>
Note: These classes can also be used for normal text.