Gradient Shine
X-ray · layers
Parameters
How this effect works
The trick is that the letters are a window, not a surface. With background-clip: text and a transparent text color, whatever you paint as the element's background shows through the letter shapes — so the gradient isn't on the text, it's behind it, cropped to it. Turn the gradient layer off and the window shows plain light gray instead; the mechanics stay identical.
The shine is simply a second background image stacked on top: a narrow bright band inside a transparent gradient, two and a half times wider than the text. Every frame we nudge its background-position, so the band slides across the window. The pause layer is what separates "expensive watch ad" from "police siren" — light that passes, rests, then passes again reads as deliberate; light that loops non-stop reads as noise.