These look like CSS custom properties (CSS variables) used to configure a small animation system. Explanation:
- -sd-animation: sd-fadeIn;
- Assigns an animation identifier (here “sd-fadeIn”) that a stylesheet or component script will interpret to apply a specific keyframe or animation behavior.
- –sd-duration: 250ms;
- Sets the animation duration to 250 milliseconds. Can be read by animation rules (e.g., animation-duration) or JS that triggers the animation.
- –sd-easing: ease-in;
- Sets the timing function (easing) for the animation; “ease-in” accelerates from slow to fast.
How they’re typically used
- In CSS:
- You’d define keyframes for sd-fadeIn and then reference the variables:
@keyframes sd-fadeIn {from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: translateY(0); }} .animated { animation-name: var(–sd-animation); animation-duration: var(–sd-duration, 250ms); animation-timing-function: var(–sd-easing, ease); animation-fill-mode: both;}
- You’d define keyframes for sd-fadeIn and then reference the variables:
- In a component library:
- A component can read these variables (from computed styles) to decide which CSS class or JS animation to run, allowing per-component overrides via inline styles or theming.
Notes and tips
- Variable naming: Use double-dash (–sd-duration) for standard CSS custom properties; the leading single-dash (-sd-animation) is unconventional but valid as an identifier if used consistently — however, it won’t be accessible via var() (var() requires the property name to start with –). So prefer –sd-animation.
- Fallbacks: Provide fallbacks when using var(), e.g., var(–sd-duration, 250ms).
- Units: Include time units (ms, s) in duration values.
- Accessibility: Keep animations short and respect prefers-reduced-motion by disabling or reducing animations when that media query is active.
If you want, I can:
- convert these into a ready-to-use CSS snippet with prefers-reduced-motion support,
- show how to read them from JS,
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