/* Data-structure simulators — shared styles */
:root {
  --ground:#eaeef3; --surface:#ffffff; --surface-2:#f4f7fb; --surface-3:#eef2f7;
  --ink:#152131; --muted:#5c6879; --faint:#8b97a6; --line:#d8dfe8;
  --accent:#2f54d6; --accent-soft:#e2e8fb; --accent-ink:#1c3aa8;
  --path:#d9821b; --path-soft:#fbe8cd;
  --prune:#b4bdc8;
  --found:#129a58; --found-soft:#d3f0e0;
  --shadow:0 1px 2px rgba(21,33,49,.06), 0 10px 30px rgba(21,33,49,.07);
  --radius:14px;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --ground:#0d1219; --surface:#151d28; --surface-2:#1b2430; --surface-3:#212c3a;
    --ink:#e7edf4; --muted:#97a3b3; --faint:#6c7a8b; --line:#2b3745;
    --accent:#6f8dff; --accent-soft:#22304e; --accent-ink:#a9bcff;
    --path:#f0a542; --path-soft:#3a2c17;
    --prune:#485565;
    --found:#38cd84; --found-soft:#14301f;
    --shadow:0 1px 2px rgba(0,0,0,.4), 0 12px 34px rgba(0,0,0,.35);
  }
}
:root[data-theme="dark"] {
  --ground:#0d1219; --surface:#151d28; --surface-2:#1b2430; --surface-3:#212c3a;
  --ink:#e7edf4; --muted:#97a3b3; --faint:#6c7a8b; --line:#2b3745;
  --accent:#6f8dff; --accent-soft:#22304e; --accent-ink:#a9bcff;
  --path:#f0a542; --path-soft:#3a2c17;
  --prune:#485565;
  --found:#38cd84; --found-soft:#14301f;
  --shadow:0 1px 2px rgba(0,0,0,.4), 0 12px 34px rgba(0,0,0,.35);
}

* { box-sizing:border-box; }
html { -webkit-text-size-adjust:100%; }
body {
  margin:0; background:var(--ground); color:var(--ink);
  font-family:"IBM Plex Sans", system-ui, sans-serif; line-height:1.6;
  -webkit-font-smoothing:antialiased;
}
.wrap { max-width:960px; margin:0 auto; padding:0 20px; }
code, .mono { font-family:"IBM Plex Mono", ui-monospace, monospace; }
a { color:var(--accent-ink); }

/* top bar with tabs */
.topbar { position:sticky; top:0; z-index:20; background:color-mix(in srgb, var(--ground) 88%, transparent);
  backdrop-filter:blur(8px); border-bottom:1px solid var(--line); }
.topbar .wrap { display:flex; align-items:center; gap:6px; padding-top:10px; padding-bottom:10px; flex-wrap:wrap; }
.brand { font-family:"Bricolage Grotesque",sans-serif; font-weight:700; font-size:1rem; letter-spacing:-.01em;
  color:var(--ink); text-decoration:none; margin-right:8px; }
.tabs { display:flex; gap:4px; flex-wrap:wrap; }
.tabs a { font-size:.88rem; font-weight:500; color:var(--muted); text-decoration:none; padding:6px 13px; border-radius:999px; }
.tabs a:hover { background:var(--surface-3); color:var(--ink); }
.tabs a[aria-current="page"] { background:var(--accent); color:#fff; }
.topbar .spacer { flex:1; }
.themebtn { border:1px solid var(--line); background:var(--surface); color:var(--muted);
  border-radius:999px; padding:6px 12px; font:inherit; font-size:.82rem; cursor:pointer; }
.themebtn:hover { color:var(--ink); border-color:var(--accent); }

/* headings + copy */
main { padding:38px 0 10px; }
.eyebrow { font-family:"IBM Plex Mono",monospace; font-size:12px; letter-spacing:.16em;
  text-transform:uppercase; color:var(--accent-ink); font-weight:500; }
h1 { font-family:"Bricolage Grotesque",sans-serif; font-weight:700;
  font-size:clamp(1.9rem, 4.6vw, 2.9rem); line-height:1.04; letter-spacing:-.015em;
  margin:.3em 0 .3em; text-wrap:balance; }
.tagline { font-size:1.08rem; color:var(--muted); max-width:64ch; margin:0 0 22px; }
h2 { font-family:"Bricolage Grotesque",sans-serif; font-weight:600; font-size:1.25rem; margin:1.6em 0 .5em; letter-spacing:-.01em; }
p, li { max-width:68ch; }
.explain p, .explain li { color:var(--muted); }
.explain ul { padding-left:1.2em; }
.explain li { margin:.25em 0; }

/* card + controls */
.card { background:var(--surface); border:1px solid var(--line); border-radius:var(--radius);
  box-shadow:var(--shadow); padding:18px; }
.controls { display:flex; gap:12px 16px; flex-wrap:wrap; align-items:flex-end; margin-bottom:14px; }
.field { display:flex; flex-direction:column; gap:5px; }
.field label { font-size:.72rem; letter-spacing:.06em; text-transform:uppercase; color:var(--faint); font-weight:600; }
input[type=number], select {
  font:inherit; font-size:.95rem; padding:8px 11px; border:1px solid var(--line);
  background:var(--surface-2); color:var(--ink); border-radius:9px; min-width:92px;
}
input:focus, select:focus { outline:2px solid var(--accent); outline-offset:1px; border-color:var(--accent); }
.btn { font:inherit; font-weight:600; font-size:.92rem; cursor:pointer; border-radius:10px; padding:9px 16px;
  border:1px solid var(--accent); background:var(--accent); color:#fff; }
.btn:hover { filter:brightness(1.06); }
.btn:active { transform:translateY(1px); }
.btn.ghost { background:var(--surface); color:var(--ink); border-color:var(--line); }
.btn.ghost:hover { border-color:var(--accent); color:var(--accent-ink); }
:focus-visible { outline:2px solid var(--accent); outline-offset:2px; }
.presets { font-size:.9rem; color:var(--muted); margin:0 0 14px; display:flex; gap:8px; align-items:center; flex-wrap:wrap; }
.presets .btn { padding:3px 9px; font-size:.82rem; }

.stage { background:var(--surface-2); border:1px solid var(--line); border-radius:11px; padding:14px; }
svg.viz, canvas.viz { display:block; width:100%; height:auto; }
.stage.spatial { max-width:472px; margin:0 auto; }

.legend { display:flex; gap:14px; flex-wrap:wrap; font-size:.82rem; color:var(--muted); margin-top:12px; }
.legend span { display:inline-flex; align-items:center; gap:6px; }
.dot { width:11px; height:11px; border-radius:3px; display:inline-block; border:1px solid rgba(0,0,0,.12); }

.readout { display:flex; gap:10px; flex-wrap:wrap; margin-top:14px; }
.stat { background:var(--surface-3); border:1px solid var(--line); border-radius:9px; padding:8px 12px; min-width:96px; }
.stat .k { font-size:.66rem; text-transform:uppercase; letter-spacing:.06em; color:var(--faint); font-weight:600; }
.stat .v { font-family:"IBM Plex Mono",monospace; font-size:1.2rem; font-weight:500; font-variant-numeric:tabular-nums; }
.stat .sub { font-size:.7rem; color:var(--muted); }
.note { font-size:.92rem; color:var(--muted); margin-top:14px; max-width:70ch; }
.note b { color:var(--ink); font-weight:600; }

/* hub cards */
.grid { display:grid; grid-template-columns:1fr 1fr; gap:16px; margin:8px 0 20px; }
@media (max-width:640px){ .grid { grid-template-columns:1fr; } }
.simcard { display:block; background:var(--surface); border:1px solid var(--line); border-radius:var(--radius);
  box-shadow:var(--shadow); padding:20px; text-decoration:none; color:var(--ink); transition:border-color .12s, transform .12s; }
.simcard:hover { border-color:var(--accent); transform:translateY(-2px); }
.simcard h3 { font-family:"Bricolage Grotesque",sans-serif; font-weight:600; font-size:1.15rem; margin:0 0 6px; }
.simcard p { color:var(--muted); font-size:.92rem; margin:0; max-width:none; }

footer { padding:34px 0 60px; color:var(--muted); font-size:.9rem; border-top:1px solid var(--line); margin-top:30px; }
footer a { text-decoration:none; border-bottom:1px solid var(--accent-soft); }
footer a:hover { border-color:var(--accent); }

/* embed mode: ?embed=1 strips the chrome so a blog can iframe just the sim */
[data-embed] .topbar, [data-embed] footer, [data-embed] main h1, [data-embed] main .tagline, [data-embed] .explain { display:none; }
[data-embed] main { padding:10px 0; }
[data-embed] body { background:var(--ground); }

@media (prefers-reduced-motion: reduce) { * { scroll-behavior:auto !important; } }