:root{
  color-scheme: light;
  --page:#f9f9f7; --surface:#fcfcfb; --ink:#0b0b0b; --ink-2:#52514e; --muted:#898781;
  --grid:#e1e0d9; --baseline:#c3c2b7; --border:rgba(11,11,11,.10);
  --s1:#2a78d6; --s2:#eb6834; --seq-250:#86b6ef; --seq-450:#2a78d6; --seq-650:#104281;
  --accent:#d03b3b;
}
@media (prefers-color-scheme: dark){
  :root:where(:not([data-theme="light"])){
    color-scheme: dark;
    --page:#0d0d0d; --surface:#1a1a19; --ink:#ffffff; --ink-2:#c3c2b7; --muted:#898781;
    --grid:#2c2c2a; --baseline:#383835; --border:rgba(255,255,255,.10);
    --s1:#3987e5; --s2:#d95926; --seq-250:#86b6ef; --seq-450:#3987e5; --seq-650:#184f95;
    --accent:#e66767;
  }
}
:root[data-theme="dark"]{
  color-scheme: dark;
  --page:#0d0d0d; --surface:#1a1a19; --ink:#ffffff; --ink-2:#c3c2b7; --muted:#898781;
  --grid:#2c2c2a; --baseline:#383835; --border:rgba(255,255,255,.10);
  --s1:#3987e5; --s2:#d95926; --seq-250:#86b6ef; --seq-450:#3987e5; --seq-650:#184f95;
  --accent:#e66767;
}
*{box-sizing:border-box}
body{margin:0;background:var(--page);color:var(--ink);font:16px/1.6 system-ui,-apple-system,"Segoe UI",sans-serif}
a{color:var(--s1)}
.wrap{max-width:1400px;margin:0 auto;padding:0 20px}
header.hero{padding:64px 0 40px;border-bottom:1px solid var(--grid);text-align:center}
.kicker{color:var(--accent);font-weight:700;letter-spacing:.08em;text-transform:uppercase;font-size:13px}
h1{font-size:clamp(30px,5vw,46px);line-height:1.15;margin:.3em 0}
.lede{font-size:19px;color:var(--ink-2);max-width:none}
header.hero .tiles{text-align:left}
nav{position:sticky;top:0;background:var(--page);border-bottom:1px solid var(--grid);z-index:5}
nav .wrap{display:flex;gap:4px;overflow-x:auto;padding:0 20px}
nav a{color:var(--ink-2);text-decoration:none;padding:12px 10px;font-size:14px;white-space:nowrap}
nav a:hover{color:var(--ink)}

/* Category-tree nav: a row of category buttons, each opening a dropdown panel below */
.nav-tree{position:sticky;top:0;background:var(--page);border-bottom:1px solid var(--grid);z-index:5;overflow:visible}
.nav-tree .wrap{display:block;padding:0 20px;overflow:visible}
.nav-cat-row{display:flex;flex-wrap:wrap;gap:2px}
.nav-cat-btn{background:none;border:none;color:var(--ink-2);text-decoration:none;padding:12px 7px;font-size:13.5px;white-space:nowrap;cursor:pointer;font-family:inherit}
.nav-cat-btn:hover,.nav-cat-btn.open{color:var(--ink)}
.nav-cat-btn.nav-overview{font-weight:700;color:var(--ink)}
.nav-panel{display:flex;flex-wrap:wrap;gap:2px;padding:8px 0 12px;border-top:1px solid var(--grid)}
.nav-panel[hidden]{display:none}
.nav-panel a{color:var(--ink-2);text-decoration:none;padding:7px 10px;font-size:13.5px;white-space:nowrap;border-radius:6px}
.nav-panel a:hover{color:var(--ink);background:var(--surface)}
section{padding:48px 0;border-bottom:1px solid var(--grid)}
h2{font-size:28px;margin:0 0 6px}
h3{font-size:19px;margin:1.6em 0 .4em}
.sub{color:var(--muted);margin:0 0 24px;font-size:15px}
.tiles{display:grid;grid-template-columns:repeat(auto-fit,minmax(190px,1fr));gap:12px;margin:28px 0 0}
.tile{background:var(--surface);border:1px solid var(--border);border-radius:10px;padding:16px 18px}
.tile-title{font-size:11px;font-weight:700;text-transform:uppercase;letter-spacing:.05em;color:var(--muted);margin-bottom:8px}
.tile .v{font-size:30px;font-weight:750;line-height:1.1}
.tile .l{color:var(--ink-2);font-size:13.5px;margin-top:4px}
.tile .d{color:var(--muted);font-size:12px;margin-top:2px}
.status-badge{display:inline-block;font-size:10.5px;font-weight:700;letter-spacing:.03em;text-transform:uppercase;padding:2px 8px;border-radius:99px;margin-bottom:8px}
.status-badge.current{background:#dcf0e2;color:#1f6b39}
.status-badge.proposed{background:#f5e6c8;color:#8a5f0b}
.tile .explain{color:var(--ink-2);font-size:12.5px;margin-top:8px;line-height:1.4;border-top:1px solid var(--border);padding-top:8px}

/* Depth toggle: four levels of explanation, from grade-9 plain language to expert/technical */
.depth-tabs{display:flex;flex-wrap:wrap;gap:6px;margin:18px 0 4px}
.depth-tab{font:inherit;font-size:13px;font-weight:600;padding:7px 13px;border-radius:99px;border:1px solid var(--border);background:var(--surface);color:var(--ink-2);cursor:pointer}
.depth-tab:hover{border-color:var(--s1)}
.depth-tab.active{background:var(--s1);border-color:var(--s1);color:#fff}
.depth-content{margin-top:14px;padding:16px 18px;border:1px solid var(--border);border-radius:10px;background:var(--surface)}
.depth-content[hidden]{display:none}
.depth-label{font-size:11px;font-weight:700;letter-spacing:.05em;text-transform:uppercase;color:var(--muted);margin-bottom:8px;display:block}

/* Expandable "show the math" panels: high-level readers see just the result,
   readers who want to dig in click to see the underlying inputs/formula. */
details.math{margin-top:8px;font-size:12px}
details.math summary{cursor:pointer;color:var(--muted);font-weight:600;list-style:none;user-select:none}
details.math summary::before{content:"▸ ";display:inline-block;transition:transform .15s}
details.math[open] summary::before{content:"▾ "}
details.math .mathbody{margin-top:8px;padding:10px 12px;background:var(--grid);border-radius:6px;font-family:ui-monospace,Consolas,monospace;font-size:11.5px;line-height:1.6;color:var(--ink-2);overflow-x:auto}
details.math table{width:100%;border-collapse:collapse;font-size:11.5px}
details.math td{padding:2px 6px 2px 0;white-space:nowrap}

/* Topic-card grid: visual entry points into the deep-dive pages */
.topic-group{margin-top:28px}
.topic-group h4{font-size:13px;text-transform:uppercase;letter-spacing:.06em;color:var(--muted);margin:0 0 10px}
.topic-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(210px,1fr));gap:12px}
.topic-card{display:block;background:var(--surface);border:1px solid var(--border);border-radius:10px;padding:14px 16px;text-decoration:none;color:var(--ink);transition:border-color .15s,transform .15s}
.topic-card:hover{border-color:var(--s1);transform:translateY(-1px)}
.topic-card .t{font-weight:700;font-size:14.5px;margin-bottom:4px}
.topic-card .s{font-size:12.5px;color:var(--ink-2);line-height:1.4}
.topic-card .badge{display:inline-block;font-size:9.5px;font-weight:700;text-transform:uppercase;letter-spacing:.04em;padding:1px 6px;border-radius:99px;margin-top:8px;background:var(--grid);color:var(--muted)}
.topic-card .badge.new{background:#dcf0e2;color:#1f6b39}
.card{background:var(--surface);border:1px solid var(--border);border-radius:12px;padding:20px 22px;margin:18px 0}
.chart{margin:10px 0 4px}
.chart .row{display:grid;grid-template-columns:minmax(120px,220px) 1fr 70px;align-items:center;gap:10px;padding:3px 0}
.chart .lbl{font-size:13.5px;color:var(--ink-2);text-align:right;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.chart .track{height:18px;position:relative}
.chart .bar{height:100%;border-radius:0 4px 4px 0;background:var(--seq-450);min-width:2px}
.chart .val{font-size:13px;color:var(--ink);font-variant-numeric:tabular-nums}
.legend{display:flex;gap:18px;flex-wrap:wrap;margin:8px 0 2px;font-size:13px;color:var(--ink-2)}
.legend .sw{display:inline-block;width:11px;height:11px;border-radius:3px;margin-right:6px;vertical-align:-1px}
.cols{display:flex;align-items:flex-end;gap:8px;height:180px;border-bottom:2px solid var(--baseline);margin-top:16px}
.cols .col{flex:1;display:flex;flex-direction:column;justify-content:flex-end;align-items:center;gap:6px;height:100%}
.cols .stick{width:70%;max-width:54px;background:var(--seq-450);border-radius:4px 4px 0 0;min-height:2px}
.cols .cv{font-size:12.5px;color:var(--ink-2);font-variant-numeric:tabular-nums}
.cols-x{display:flex;gap:8px;margin-top:6px}
.cols-x span{flex:1;text-align:center;font-size:12.5px;color:var(--muted)}
table{border-collapse:collapse;width:100%;font-size:14px}
th{text-align:left;color:var(--muted);font-weight:600;border-bottom:2px solid var(--baseline);padding:8px 10px}
td{border-bottom:1px solid var(--grid);padding:8px 10px;vertical-align:top}
td.num{text-align:right;font-variant-numeric:tabular-nums;white-space:nowrap}
.scroll{overflow-x:auto}
.tag{display:inline-block;font-size:11.5px;padding:1px 8px;border-radius:99px;border:1px solid var(--border);color:var(--ink-2);white-space:nowrap}
.phase{border-left:3px solid var(--s1);padding-left:18px;margin:26px 0}
.phase h3{margin-top:0}
.phase ul{margin:8px 0;padding-left:20px}
.phase li{margin:6px 0}
.market{margin:14px 0}
.market h4{margin:0 0 2px;font-size:16px}
.market p{margin:2px 0;color:var(--ink-2);font-size:14.5px}
.market .conf{font-size:12.5px;color:var(--muted)}
.market ul{margin:6px 0 0;padding-left:18px}
.market ul li{font-size:13px;color:var(--muted);margin:3px 0}
.note{background:var(--surface);border-left:3px solid var(--s2);border-radius:0 10px 10px 0;padding:14px 18px;margin:20px 0;font-size:15px;color:var(--ink-2)}
footer{padding:40px 0 60px;color:var(--muted);font-size:13.5px}
.provenance{font-size:12px;color:var(--muted)}
@media (max-width:640px){.chart .row{grid-template-columns:minmax(90px,120px) 1fr 60px}}