Hey 
You can preview it in the Editor by adding an HTML Embed in the page with a style tag inside.
In the styles, you can target a tag or a class. If you target a class, don’t forget to add it in the Settings panel of the text.
<style>
.gradient-text {
background: linear-gradient(45deg, #f3ec78, #af4261);
-webkit-background-clip: text;
-webkit-text-fill-color: transparent;
}
</style>
