Skeleton Loader

---
export const meta = {
  title: "Skeleton Loader",
  tags: ["transitions", "loading", "shimmer", "skeleton"],
  description:
    "A content card that opens as shimmering skeleton placeholders — avatar, text lines, image block — swept by an animated gradient, then crossfades to real content after a short delay. A Reload button replays the load; under reduced-motion the shimmer stops and content shows at once.",
  tech: ["CSS gradient sweep", "crossfade opacity", "prefers-reduced-motion"],
  interactive: true,
  height: 420,
};
---

<section class="skl-stage">
  <article class="skl-card" data-skl data-state="loading" aria-busy="true">
    <!-- Skeleton layer -->
    <div class="skl-skeleton" data-skl-skeleton aria-hidden="true">
      <div class="skl-row">
        <div class="skl-bone skl-avatar"></div>
        <div class="skl-stack">
          <div class="skl-bone skl-line" style="width: 55%"></div>
          <div class="skl-bone skl-line skl-line--sm" style="width: 35%"></div>
        </div>
      </div>
      <div class="skl-bone skl-image"></div>
      <div class="skl-bone skl-line" style="width: 92%"></div>
      <div class="skl-bone skl-line" style="width: 80%"></div>
      <div class="skl-bone skl-line" style="width: 64%"></div>
      <div class="skl-row skl-row--foot">
        <div class="skl-bone skl-pill"></div>
        <div class="skl-bone skl-pill" style="width: 4.5rem"></div>
      </div>
    </div>

    <!-- Real content layer -->
    <div class="skl-content" data-skl-content>
      <header class="skl-head">
        <span class="skl-photo" aria-hidden="true">◈</span>
        <div>
          <p class="skl-name">Nova Sinclair</p>
          <p class="skl-meta">Design Engineer · 3 min read</p>
        </div>
      </header>
      <div class="skl-hero" aria-hidden="true">
        <span class="skl-hero-glow"></span>
      </div>
      <h3 class="skl-title">Designing motion that respects the user</h3>
      <p class="skl-body">
        Great loading states aren't an afterthought — they set the rhythm of the
        whole interface. A well-tuned shimmer tells you the wait is deliberate,
        the content is coming, and the product is alive.
      </p>
      <footer class="skl-tags" aria-label="Tags">
        <span class="skl-tag">Motion</span>
        <span class="skl-tag">UX</span>
      </footer>
    </div>

    <button type="button" class="skl-reload" data-skl-reload>
      <span class="skl-reload-ic" aria-hidden="true">↻</span>
      Reload
    </button>
  </article>
</section>

<style>
  .skl-stage {
    min-height: 420px;
    display: grid;
    place-items: center;
    padding: 2.5rem 1.5rem;
    background:
      radial-gradient(50rem 30rem at 80% -10%, color-mix(in oklab, var(--spectrum-3, #45d3e8) 12%, transparent), transparent 65%),
      var(--bg-sunk, #0b0c15);
    font-family: var(--font-sans, system-ui, sans-serif);
  }

  .skl-card {
    position: relative;
    width: min(30rem, 100%);
    padding: 1.4rem;
    border-radius: var(--radius-l, 22px);
    border: 1px solid var(--border, #2a2c3a);
    background: var(--surface, #16171f);
    box-shadow: var(--shadow-l, 0 20px 50px rgba(0, 0, 0, 0.45));
    color: var(--ink, #f2f2f7);
    overflow: hidden;
  }

  /* Crossfade: stack skeleton + content, toggle opacity by [data-state] */
  .skl-skeleton,
  .skl-content {
    transition: opacity var(--dur, 320ms) var(--ease-out, ease);
  }
  .skl-content {
    display: grid;
    gap: 0.9rem;
  }
  .skl-card[data-state="loading"] .skl-content {
    opacity: 0;
    /* keep it laid out (so height is stable) but non-interactive & stacked */
    position: absolute;
    inset: 1.4rem;
    pointer-events: none;
  }
  .skl-card[data-state="ready"] .skl-skeleton {
    opacity: 0;
    position: absolute;
    inset: 1.4rem;
    pointer-events: none;
  }
  .skl-card[data-state="ready"] .skl-content { opacity: 1; }

  /* --- Skeleton bones --------------------------------------------------- */
  .skl-skeleton { display: grid; gap: 0.9rem; }
  .skl-row { display: flex; align-items: center; gap: 0.85rem; }
  .skl-row--foot { margin-top: 0.2rem; }
  .skl-stack { flex: 1; display: grid; gap: 0.5rem; }

  .skl-bone {
    position: relative;
    border-radius: 8px;
    background: color-mix(in oklab, var(--ink-faint, #8a8c9c) 22%, var(--surface-2, #24252f));
    overflow: hidden;
  }
  .skl-avatar { width: 3rem; height: 3rem; border-radius: 50%; flex: none; }
  .skl-line { height: 0.85rem; }
  .skl-line--sm { height: 0.7rem; }
  .skl-image { height: 8rem; border-radius: var(--radius-m, 14px); }
  .skl-pill { width: 5.5rem; height: 1.6rem; border-radius: var(--radius-round, 999px); }

  /* shimmer sweep */
  .skl-bone::after {
    content: "";
    position: absolute;
    inset: 0;
    background: linear-gradient(
      100deg,
      transparent 20%,
      color-mix(in oklab, #fff 22%, transparent) 50%,
      transparent 80%
    );
    transform: translateX(-100%);
    animation: skl-sweep 1.4s var(--ease-in-out, ease) infinite;
  }
  @keyframes skl-sweep { to { transform: translateX(100%); } }

  /* --- Real content ----------------------------------------------------- */
  .skl-head { display: flex; align-items: center; gap: 0.85rem; }
  .skl-photo {
    display: grid;
    place-items: center;
    width: 3rem;
    height: 3rem;
    flex: none;
    border-radius: 50%;
    font-size: 1.3rem;
    color: #fff;
    background: linear-gradient(150deg, var(--spectrum-1, #8b5cf6), var(--spectrum-3, #45d3e8));
  }
  .skl-name { margin: 0; font-weight: 600; color: var(--ink, #fff); }
  .skl-meta { margin: 0.1rem 0 0; font-size: 0.82rem; color: var(--ink-faint, #8a8c9c); }

  .skl-hero {
    position: relative;
    height: 8rem;
    border-radius: var(--radius-m, 14px);
    overflow: hidden;
    background: linear-gradient(135deg,
      color-mix(in oklab, var(--spectrum-1, #8b5cf6) 40%, var(--bg, #0e0f1a)),
      color-mix(in oklab, var(--spectrum-3, #45d3e8) 40%, var(--bg, #0e0f1a)));
  }
  .skl-hero-glow {
    position: absolute;
    inset: -30% 40% auto -10%;
    height: 120%;
    background: radial-gradient(circle, color-mix(in oklab, var(--spectrum-5, #fbbf24) 60%, transparent), transparent 60%);
    filter: blur(24px);
  }

  .skl-title { margin: 0; font-size: 1.2rem; letter-spacing: -0.01em; color: var(--ink, #fff); }
  .skl-body { margin: 0; line-height: 1.55; color: var(--ink-muted, #b7b9c9); font-size: 0.92rem; }
  .skl-tags { display: flex; gap: 0.5rem; }
  .skl-tag {
    padding: 0.3rem 0.8rem;
    border-radius: var(--radius-round, 999px);
    font-size: 0.78rem;
    color: var(--spectrum-3, #45d3e8);
    background: color-mix(in oklab, var(--spectrum-3, #45d3e8) 14%, transparent);
    border: 1px solid color-mix(in oklab, var(--spectrum-3, #45d3e8) 30%, transparent);
  }

  /* --- Reload ----------------------------------------------------------- */
  .skl-reload {
    position: absolute;
    top: 1rem;
    right: 1rem;
    z-index: 2;
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.4rem 0.75rem;
    border-radius: var(--radius-round, 999px);
    border: 1px solid var(--border-strong, #3a3d4d);
    background: color-mix(in oklab, var(--surface-2, #24252f) 85%, transparent);
    color: var(--ink, #fff);
    font: inherit;
    font-size: 0.8rem;
    cursor: pointer;
    backdrop-filter: blur(6px);
    -webkit-backdrop-filter: blur(6px);
    transition: transform var(--dur-fast, 160ms) var(--ease-out, ease),
      border-color var(--dur-fast, 160ms) var(--ease-out, ease);
  }
  .skl-reload:hover { transform: translateY(-1px); border-color: var(--spectrum-3, #45d3e8); }
  .skl-reload-ic { display: inline-block; font-size: 0.95rem; }
  .skl-card[data-state="loading"] .skl-reload-ic { animation: skl-spin 0.9s linear infinite; }
  @keyframes skl-spin { to { transform: rotate(360deg); } }

  @media (prefers-reduced-motion: reduce) {
    .skl-bone::after { animation: none; opacity: 0.4; }
    .skl-reload-ic,
    .skl-card[data-state="loading"] .skl-reload-ic { animation: none; }
    .skl-skeleton,
    .skl-content,
    .skl-reload { transition: none; }
  }
</style>

<script>
  (function () {
    function bind() {
      document.querySelectorAll<HTMLElement>("[data-skl]").forEach((card) => {
        if (card.dataset.bound) return;
        card.dataset.bound = "1";

        const reload = card.querySelector<HTMLButtonElement>("[data-skl-reload]");
        const reduce = matchMedia("(prefers-reduced-motion: reduce)").matches;
        let timer = 0;

        function ready() {
          card.dataset.state = "ready";
          card.setAttribute("aria-busy", "false");
        }
        function load() {
          clearTimeout(timer);
          if (reduce) { ready(); return; } // no artificial wait under reduced-motion
          card.dataset.state = "loading";
          card.setAttribute("aria-busy", "true");
          timer = window.setTimeout(ready, 2000);
        }

        // Kick off the initial load once bound (markup ships in "loading").
        load();
        reload?.addEventListener("click", load);
      });
    }
    document.addEventListener("astro:page-load", bind);
    if (document.readyState !== "loading") bind();
  })();
</script>