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css-alpha-masking

css-alpha-masking

github.com/mengtoDesign & UI7.1k1.5k installsUpdated 3d ago
Repository

About css-alpha-masking

A design skill for adding directional alpha fades to CSS elements. It guides developers through mask settings, browser fallback, and small adjustments to fade direction and strength.

Key features

  1. 01Horizontal and vertical alpha fades
  2. 02Safari mask-image fallback
  3. 03Adjustable fade direction and stop positions
  4. 04Guidance on visible content and masks

Use cases

  1. 01Fade the edges of an image or text
  2. 02Apply a top-to-bottom container fade
  3. 03Tune fade width and softness

Install

Copy the command and run it in a terminal.

$npx skills add https://github.com/mengto/skills --skill css-alpha-masking

After installing, type/css-alpha-maskingin Claude Code to confirm it loaded.

Bundled filesdemo/index.htmldemo/PROMPT.md

Details

From the project README

CSS Alpha Masking Skill

Workflow

  1. Confirm direction (horizontal or vertical) and fade stop percentages.
  2. Provide the inline CSS snippet and any needed class usage.
  3. Offer small tweaks only (direction, stop positions, colors).

Usage checklist

  • Apply the mask styles directly on the element or in a CSS class.
  • Always include both mask-image and -webkit-mask-image for Safari.
  • Ensure the element has visible content; masks reveal/hide alpha only.

Horizontal (left/right) fade

/* Add this inline CSS to any element */
mask-image: linear-gradient(to right, transparent, black 15%, black 85%, transparent);
-webkit-mask-image: linear-gradient(to right, transparent, black 15%, black 85%, transparent);

Vertical (top/bottom) fade

/* Add this inline CSS to any element */
mask-image: linear-gradient(to bottom, transparent, black 15%, black 85%, transparent);
-webkit-mask-image: linear-gradient(to bottom, transparent, black 15%, black 85%, transparent);

Customization knobs

  • Direction: to right, to left, to bottom, to top.
  • Fade depth: adjust 15% and 85% stops.
  • Strength: change transparent to rgba(0,0,0,0.2) for softer fades.

Common pitfalls

  • Forgetting the -webkit-mask-image fallback in Safari.
  • Expecting masks to work on elements with overflow: hidden but no visible content behind.

Questions to ask when specs are missing

  • Which direction should the fade go?
  • How wide should the fade edges be?
  • Is this for images, text, or a container background?

Comments

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