# Skeleton → content

Subtle web animation sketch from [https://mighil.com/animations](https://mighil.com/animations).

- **Live demo:** https://mighil.com/animations/skeleton-content
- **Standalone HTML:** https://mighil.com/animations/skeleton-content?download=1
- **This file:** https://mighil.com/animations/skeleton-content/skeleton-content.md
- **Technique:** `loading`

## What it does

Shimmer holds the space, then content fades in.

## Instructions for AI / coding agents

Implement this micro-interaction in the user's stack (vanilla HTML, React, Vue, Svelte, etc.).

1. Use the **HTML** as the DOM structure (adapt JSX/templates as needed; keep class names and ids).
2. Include the **Theme** CSS (or map the same variables into the host design system). It switches light/dark with `prefers-color-scheme`.
3. Apply the **CSS** as-is when possible. It uses `var(--text-color)`, `var(--heading-color)`, `var(--background-color)`, etc. from the theme so both modes work.
4. Run the **JavaScript** after the markup mounts. Prefer `DOMContentLoaded` or a framework `useEffect` / `onMount`.
5. Keep motion respectful of `prefers-reduced-motion` if the snippet already checks it.
6. Do not depend on mighil.com runtime or fonts. Theme variables are enough for color.
7. If porting to a component, expose the interactive root via a ref and preserve accessibility attributes (`aria-*`, `role`, `button` types).

## Theme (auto light / dark)

```css
/* Auto light / dark — follows prefers-color-scheme */
:root{
  color-scheme: light dark;
  --text-color: hsl(0, 0%, 18%);
  --heading-color: hsl(0, 0%, 18%);
  --background-color: hsl(0, 0%, 99%);
  --bg-color: hsl(0, 0%, 99%);
  --link-color: hsl(0, 0%, 18%);
  --visited-color: hsl(0, 0%, 18%);
  --blockquote-color: hsl(0, 0%, 18%);
  --code-bg-color: hsl(0, 0%, 95%);
  --code-color: hsl(0, 0%, 18%);
  --sub-color: hsl(0, 0%, 29%);
}
@media (prefers-color-scheme: dark){
:root{
  --text-color: hsl(35, 25%, 85%);
  --heading-color: hsl(35.2, 32.6%, 82.5%);
  --background-color: hsl(60, 2.2%, 8.8%);
  --bg-color: hsl(60, 2.2%, 8.8%);
  --link-color: hsl(34.7, 55.3%, 79.8%);
  --visited-color: hsla(34.7, 55.3%, 79.8%, 0.85);
  --blockquote-color: hsl(35, 30%, 75%);
  --code-bg-color: hsl(30, 5%, 7.8%);
  --code-color: limegreen;
  --sub-color: hsla(34.7, 24.7%, 84.9%, 0.78);
}
}
```

## HTML

```html
<div class="skel-wrap" id="skel-wrap">
        <div class="skel-card" aria-hidden="true">
          <div class="skel-line w80"></div>
          <div class="skel-line"></div>
          <div class="skel-line"></div>
        </div>
        <div class="skel-content">
          <strong>Project brief</strong>
          <p>Content fades up once the placeholder has done its job.</p>
        </div>
      </div>
```

## CSS

```css
@keyframes skel-shine{to{background-position:-200% 0}}

@keyframes skel-in{to{opacity:1;transform:translateY(0)}}

.skel-wrap{width:min(100%,300px)}

.skel-card,.skel-content{
  box-sizing:border-box;border-radius:10px;padding:14px;
  border:1px solid color-mix(in srgb,var(--text-color) 10%,transparent);
}

.skel-line{
  height:10px;border-radius:4px;margin-bottom:10px;
  background:linear-gradient(90deg,
    color-mix(in srgb,var(--text-color) 8%,transparent) 0%,
    color-mix(in srgb,var(--text-color) 14%,transparent) 50%,
    color-mix(in srgb,var(--text-color) 8%,transparent) 100%);
  background-size:200% 100%;
  animation:skel-shine 1.2s ease-in-out infinite;
}

.skel-line:last-child{margin-bottom:0;width:62%}

.skel-line.w80{width:80%}

.skel-content{display:none;opacity:0;transform:translateY(6px)}

.skel-wrap.is-ready .skel-card{display:none}

.skel-wrap.is-ready .skel-content{
  display:block;animation:skel-in .4s cubic-bezier(.22,1,.36,1) forwards;
}

.skel-content strong{display:block;margin-bottom:6px;font-size:.95rem;font-weight:500}

.skel-content p{margin:0;font-size:.85rem;color:color-mix(in srgb,var(--text-color) 65%,transparent);line-height:1.45}

@media (prefers-reduced-motion: reduce){
  .breath-dot,.breath-ring,.wave.is-live span,.ink-drop,
  .marquee-track,
  .skel-line,.save-btn.is-loading .spin,.badge.is-bump,.like-btn.is-pop,.save-status.is-saving .dot,.stars button.is-pop svg,
  .field.is-invalid input,.save-btn.is-done .check path,.ux-check[aria-checked="true"] .ux-box path,.char-meta.is-warn,.success-banner.is-on path,
  .typing span,.conn-dot,.indet > i,.toast.is-on .toast-timer > i,.stagger-list.is-in .stagger-item,.submit-wrap.is-loading .submit-ring rect,.submit-wrap.is-settle,.hold-btn.is-settle,.confirm-btn.is-settle,.sync-btn.is-settle,.invite-btn.is-settle,.retry-btn.is-shake-err,.retry-btn.is-shake-ok,.cart-badge.is-pop,.mute-btn .x-line,.presence.is-ping .presence-dot::after,.tag-chip,.nudge-field.is-nudge,.tilt-scene:hover .tilt-tile::before,.demo-replay.is-tap,.hit.is-tap,.stack-toggle.is-tap,.nudge-btn.is-tap,.wipe.is-tap,.save-btn.is-tap,.copy-btn.is-tap,.like-btn.is-tap,.pin-btn.is-tap,.retry-btn.is-tap,.wizard-nav button.is-tap,.mute-btn.is-tap,
  .scan:hover::after,.scan.is-on::after,.cascade.is-in b,.stepper-val.is-bump,.otp input.is-pop,.rel-time.is-live .rel-dot,.sync-btn.is-spin .sync-arrows,.ok-field.is-ok .ok-check path,.unread-row.is-read .unread-check path,.mic-btn.is-on::before,.mic-btn.is-on::after,.ghost-wrap.is-flash,.cmd-palette li.is-run,.flag-row.is-warn,.mention.is-flash b{animation:none!important}

  .skel-wrap.is-ready .skel-content{opacity:1;transform:none;animation:none}
}
```

## JavaScript

```js
const skelWrap = document.getElementById('skel-wrap');
  function runSkel() {
    if (!skelWrap) return;
    skelWrap.classList.remove('is-ready');
    setTimeout(() => skelWrap.classList.add('is-ready'), reduce ? 200 : 1100);
  }
  setTimeout(runSkel, 600);

document.querySelectorAll('[data-act]').forEach((btn) => {
    btn.addEventListener('click', (e) => {
      e.stopPropagation();
      const act = btn.getAttribute('data-act');
      if (act === 'skel') runSkel();
    });
  });
```

---

_Source: https://mighil.com/animations/skeleton-content_