:root{
      /* Polar Pop palette */
      --polar-deep:#065758; --polar-ice:#E2F0EF; --polar-mist:#A9D4D6; --polar-sea:#82C3C5; --polar-coral:#C46960;
      /* Theme */
      --bg:#065758; --bg-elev:#0c4a4c; --text:#E2F0EF; --muted:#A9D4D6; --card:#082f30; --accent:#C46960; --accent-2:#82C3C5;
      --ring: 0 0 0 2px color-mix(in oklab, var(--accent) 45%, transparent);
      --radius: 18px; --shadow: 0 10px 30px rgba(0,0,0,.35); --container: 1100px;
      --header-offset: 96px; --toc-height: 44px;
    }

    html{scroll-behavior:smooth} *{box-sizing:border-box}
    body{ margin:0; background: var(--bg); color: var(--text); font: 16px/1.6 system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, 'Helvetica Neue', Arial, sans-serif; }
    a{ color:var(--accent); text-decoration:none } a:hover{ filter:brightness(1.1) saturate(1.05) }

    /* Header */
    header{ position:sticky; top:0; z-index:50; backdrop-filter:saturate(140%) blur(8px); background: color-mix(in oklab, var(--bg) 90%, transparent); border-bottom:1px solid color-mix(in oklab, var(--accent) 40%, transparent) }
    .nav{ max-width:var(--container); margin:auto; display:flex; align-items:center; justify-content:space-between; gap:16px; padding:14px 20px }
    .brand{ display:flex; align-items:center; gap:12px; font-weight:900; letter-spacing:.5px }
    .brand .logo-img{ width:36px; height:36px; border-radius:10px; box-shadow:var(--shadow); background:var(--bg-elev); object-fit:contain; padding:2px }
    /* Top-right coral button */
    .nav a.top-btn{ background: var(--accent); color:#fff; border:1px solid color-mix(in oklab, var(--accent) 60%, transparent) }

    /* Hero */
    .hero{ background: radial-gradient(900px 600px at 12% -10%, color-mix(in oklab, var(--polar-coral) 22%, transparent), transparent 70%), radial-gradient(900px 600px at 100% 0%, color-mix(in oklab, var(--polar-sea) 22%, transparent), transparent 70%), color-mix(in oklab, var(--polar-ice) 14%, var(--bg)); }
    .wrap{ max-width:var(--container); margin:auto; padding: 28px 20px }
    .hero h1{ font-size: clamp(28px, 4.2vw, 54px); margin: 10px 0 4px }
    .hero p{ color:var(--muted); margin: 0 0 18px }
    .hero-image{ margin-top:14px; border-radius: var(--radius); overflow:hidden; border:1px solid color-mix(in oklab, var(--text) 10%, transparent); box-shadow: var(--shadow); background: var(--bg-elev); }
    .hero-image img{ width:100%; height: clamp(180px, 28vw, 340px); object-fit: cover; display:block }

    /* Sticky TOC bar */
    .toc-bar{ position:sticky; top:calc(var(--header-offset) - 1px); z-index:49; backdrop-filter:saturate(140%) blur(6px); background: color-mix(in oklab, var(--bg) 90%, transparent); border-bottom:1px solid color-mix(in oklab, var(--accent) 30%, transparent); }
    .toc-bar .wrap{ padding:8px 20px; max-width:var(--container); margin:auto; }
    .toc{ display:flex; flex-wrap:wrap; gap:8px; justify-content:center }
    .toc a{ display:inline-flex; align-items:center; padding:8px 12px; border-radius:12px; border:1px solid color-mix(in oklab, var(--text) 10%, transparent); background: var(--bg-elev); color:var(--text) }

    /* Sections */
    section[id]{ scroll-margin-top: calc(var(--header-offset) + var(--toc-height)); }
    main section{ padding: 30px 0 }
    h2{ font-size: clamp(22px, 2.6vw, 34px); margin: 0 0 8px }
    h3{ font-size: clamp(18px, 2.2vw, 24px); margin: 18px 0 6px }
    p.lead{ color:var(--muted) }

    /* Layout */
    .two-col{ display:grid; grid-template-columns: 1fr 1fr; gap: 18px }
    @media (max-width: 900px){ .two-col{ grid-template-columns: 1fr } }
    .grid{ display:grid; grid-template-columns: repeat(3, minmax(0,1fr)); gap:18px }
    @media (max-width: 900px){ .grid{ grid-template-columns: 1fr } }

    /* Card & helpers */
    .card{ background:linear-gradient(180deg, color-mix(in oklab, var(--card) 86%, transparent), color-mix(in oklab, var(--bg) 40%, transparent)); border:1px solid color-mix(in oklab, var(--text) 8%, transparent); border-radius: var(--radius); padding:16px; box-shadow: var(--shadow); display:flex; flex-direction:column }
    .callout{ border-left: 4px solid var(--accent); padding: 10px 14px; background: color-mix(in oklab, var(--polar-ice) 12%, var(--bg)); border-radius: 10px }

    /* Buttons, badge */
    .btn{ display:inline-flex; align-items:center; gap:10px; padding:10px 14px; border-radius:12px; border:1px solid color-mix(in oklab, var(--text) 10%, transparent); background:var(--bg-elev); color:var(--text); box-shadow:var(--shadow); text-decoration:none }
    .btn.primary{ background:linear-gradient(135deg, var(--accent), var(--accent-2)); color:#fff; border:0 }
    .badge{ font-size:12px; background:var(--accent-2); color:#fff; padding:4px 8px; border-radius:999px; border:none }

    /* Footer */
    footer{ border-top:1px solid color-mix(in oklab, var(--accent) 40%, transparent); background: radial-gradient(circle at 50% -30%, color-mix(in oklab, var(--polar-ice) 15%, transparent), transparent 80%), color-mix(in oklab, var(--polar-ice) 10%, var(--bg)); }
    .foot{ max-width:var(--container); margin:auto; padding:28px 20px; color:var(--muted); display:flex; flex-wrap:wrap; gap:16px; align-items:center; justify-content:space-between }

    .sr-only{ position:absolute; width:1px; height:1px; padding:0; margin:-1px; overflow:hidden; clip:rect(0,0,0,0); white-space:nowrap; border:0 }

    /* Bottom-right coral FAB */
    #toTop{ position:fixed; right:18px; bottom:18px; opacity:0; transform:translateY(10px); transition: all .15s ease;
      background: var(--accent); color:#fff; border:1px solid color-mix(in oklab, var(--accent) 60%, transparent); }
    #toTop.show{ opacity:1; transform:none }

    /* Video embed (responsive, centered, smaller) */
    .video-embed{ margin:12px auto 0; width:60%; min-width:280px; border-radius:12px; overflow:hidden; border:1px solid color-mix(in oklab, var(--text) 10%, transparent); box-shadow:var(--shadow); background:#000; aspect-ratio:16/9 }
    .video-embed iframe{ width:100%; height:100%; border:0; display:block }
    @media (max-width: 800px){ .video-embed{ width:100%; } }

    /* Essentials card links pinned to bottom */
    #essentials .two-col .card p:last-of-type{ margin-top:auto }
	
	/* ——— Sparkles ——— */
    .sparkle-host{ position:relative; isolation:isolate }
    .sparkle{
    position:absolute; z-index:2; left:0; top:0; pointer-events:none;
	width:6px; height:6px; border-radius:50%;
	background: radial-gradient(closest-side, #fff, rgba(255,255,255,.8) 55%, rgba(255,255,255,0));
	filter: drop-shadow(0 0 6px rgba(255,255,255,.35))
		drop-shadow(0 0 10px color-mix(in oklab, var(--accent) 60%, transparent));
	transform: translate(-50%,-50%); /* center on spawn point */
	animation: sparkle-move .9s ease-out forwards;
	}
	@keyframes sparkle-move{
	0%   { opacity:1;   transform: translate(-50%,-50%) scale(1); }
	100% { opacity:0;   transform: translate(calc(-50% + var(--dx,0px)), calc(-50% + var(--dy,0px))) scale(0); }
	}
	@media (prefers-reduced-motion: reduce){ .sparkle{ display:none } }