Turn a visual or interaction technique you already built into a reusable web-design skill, by isolating the one mechanism that makes it work while reproducing its approved reference exactly around that focus, and packaging it with a demo that proves both the mechanism and the visual fidelity. Covers finding the mechanism, naming the technique plainly, disclosing the verified runtime and renderer, auditing reference layers, carrying real numbers instead of adjectives, preserving owned staging, keeping expensive gotchas, declaring the boundary against neighbouring skills, and browser-verifying before claiming it works. Use when a page, canvas scene, shader, scroll effect, layout system, or hover interaction turned out well and should become a skill rather than staying in one project.