Quick Tip: How to Add Gradient Effects and Patterns to Text - SitePoint
Briefly

To create the effect we're after, we first set the color of the element to transparent. In the code below, we're styling an <h1> heading.
Let's first try setting a gradient effect on our heading text: Here, we've set a left-to-right gradient that will span the heading text.
Read at Sitepoint
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