/* ARC Proofing — aesthetic system (locked per ARC_PROOF_BRAND.md §6)
   Pure neutral-950. White on charcoal. No per-vertical color. Mono for URLs/hashes/IDs. */

:root {
  /* neutral scale */
  --n-950: #0a0a0a;
  --n-925: #0e0e0e;
  --n-900: #141414;
  --n-880: #181818;
  --n-850: #1c1c1c;
  --n-800: #242424;
  --n-700: #363636;
  --n-650: #444;
  --n-600: #565656;
  --n-500: #727272;
  --n-400: #9a9a9a;
  --n-300: #c4c4c4;
  --n-200: #dcdcdc;
  --n-100: #f0f0f0;
  --n-050: #fafafa;

  --bg: var(--n-950);
  --fg: var(--n-100);

  /* typography (tweakable) */
  --font-sans: 'Geist', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, 'SFMono-Regular', Menlo, monospace;

  --head-weight: 500;
  --head-track: -0.025em;

  /* density (tweakable) — section vertical rhythm */
  --gap: 1px;
  --sec-pad: 88px;
  --max: 960px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-sans);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

::selection { background: var(--n-100); color: var(--n-950); }

a { color: inherit; text-decoration: none; }
button { font-family: inherit; cursor: pointer; }

.mono { font-family: var(--font-mono); font-feature-settings: 'zero' 1; }

/* ---- shell ---- */
.shell { min-height: 100vh; }
.wrap { max-width: var(--max); margin: 0 auto; padding-left: 32px; padding-right: 32px; }

/* ---- nav ---- */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--n-950) 88%, transparent);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--n-880);
}
.nav-in { display: flex; align-items: center; justify-content: space-between; height: 58px; }
.wordmark { display: flex; align-items: baseline; font-size: 15px; letter-spacing: -0.02em; font-weight: 500; }
.wordmark .dim { color: var(--n-500); }
.wordmark .lit { color: var(--n-100); }
.nav-links { display: flex; align-items: center; gap: 26px; }
.nav-links a { font-size: 12.5px; color: var(--n-500); transition: color .25s; letter-spacing: -0.01em; }
.nav-links a:hover { color: var(--n-200); }
.btn-line {
  font-size: 10.5px; letter-spacing: 0.16em; text-transform: uppercase; white-space: nowrap;
  color: var(--n-100); padding: 8px 15px; border: 1px solid var(--n-700);
  background: transparent; transition: border-color .25s, background .25s;
}
.btn-line:hover { border-color: var(--n-400); }

/* ---- subdomain selector ---- */
.selector {
  position: sticky; top: 58px; z-index: 40;
  background: color-mix(in srgb, var(--n-950) 90%, transparent);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--n-900);
}
.selector-in { display: flex; gap: 4px; padding: 9px 0; overflow-x: auto; scrollbar-width: none; }
.selector-in::-webkit-scrollbar { display: none; }
.sel-item {
  font-family: var(--font-mono); font-size: 12px; white-space: nowrap;
  padding: 5px 12px; color: var(--n-500); background: transparent; border: 0;
  transition: color .2s, background .2s;
}
.sel-item:hover { color: var(--n-200); background: var(--n-880); }
.sel-item.active { color: var(--n-950); background: var(--n-100); }

/* ---- section frame ---- */
.sec { border-top: 1px solid var(--n-880); padding: var(--sec-pad) 0; }
.sec:first-of-type { border-top: 0; }
.eyebrow {
  font-family: var(--font-mono); font-size: 10.5px; letter-spacing: 0.2em;
  text-transform: uppercase; color: var(--n-600); margin: 0 0 26px;
}

/* ---- hero ---- */
.hero { padding-top: 92px; padding-bottom: var(--sec-pad); }
.hero-url { font-family: var(--font-mono); font-size: 13px; color: var(--n-500); margin: 0 0 22px; letter-spacing: 0; }
.hero-h1 {
  font-size: clamp(38px, 6.4vw, 70px); line-height: 1.02;
  font-weight: var(--head-weight); letter-spacing: var(--head-track);
  margin: 0 0 28px; text-wrap: balance;
}
.hero-h1 .dim { color: var(--n-600); display: block; }
.hero-h1 .lit { color: var(--n-050); }
.hero-stack { display: block; }
.hero-stack .line { display: block; color: var(--n-700); transition: color .5s; }
.hero-stack .line.on { color: var(--n-050); }
.hero-lead { font-size: 18px; line-height: 1.62; color: var(--n-400); max-width: 600px; margin: 0 0 38px; font-weight: 400; }
.hero-cta { display: flex; gap: 14px; align-items: center; flex-wrap: wrap; margin-bottom: 52px; }
.btn-fill {
  font-size: 11px; letter-spacing: 0.16em; text-transform: uppercase; font-weight: 500; white-space: nowrap;
  color: var(--n-950); background: var(--n-100); border: 1px solid var(--n-100);
  padding: 13px 22px; display: inline-flex; align-items: center; gap: 9px;
  transition: background .25s, transform .15s;
}
.btn-fill:hover { background: #fff; }
.btn-fill:active { transform: translateY(1px); }
.btn-ghost {
  font-size: 11px; letter-spacing: 0.16em; text-transform: uppercase; white-space: nowrap;
  color: var(--n-300); background: transparent; border: 1px solid var(--n-700);
  padding: 13px 22px; transition: border-color .25s, color .25s;
}
.btn-ghost:hover { border-color: var(--n-400); color: var(--n-100); }
.hero-market { font-family: var(--font-mono); font-size: 12px; color: var(--n-600); }
.hero-market::before { content: '◆ '; color: var(--n-700); }

/* ---- frameworks pills ---- */
.pills { display: flex; flex-wrap: wrap; gap: 8px; }
.pill {
  font-family: var(--font-mono); font-size: 11.5px; color: var(--n-400);
  padding: 7px 12px; border: 1px solid var(--n-800); background: var(--n-900);
  transition: border-color .2s, color .2s;
}
.pill:hover { border-color: var(--n-650); color: var(--n-200); }

/* ---- outcomes ---- */
.outcomes { display: grid; gap: 0; }
.outcome { display: grid; grid-template-columns: 30px 1fr; gap: 22px; padding: 26px 0; border-top: 1px solid var(--n-900); }
.outcome:first-child { border-top: 0; padding-top: 0; }
.outcome .idx { font-family: var(--font-mono); font-size: 12px; color: var(--n-600); padding-top: 3px; }
.outcome h3 { font-size: 16px; font-weight: 500; color: var(--n-100); margin: 0 0 7px; letter-spacing: -0.01em; }
.outcome p { font-size: 15px; line-height: 1.6; color: var(--n-500); margin: 0; max-width: 640px; }

/* ---- capabilities ---- */
.caps { list-style: none; padding: 0; margin: 0; display: grid; gap: 16px; }
.caps li { display: grid; grid-template-columns: 16px 1fr; gap: 14px; align-items: start; }
.caps .tick { color: var(--n-500); font-family: var(--font-mono); font-size: 13px; padding-top: 1px; }
.caps span.txt { font-size: 15px; line-height: 1.55; color: var(--n-300); }

/* ---- pricing ---- */
.prices { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
.price { border: 1px solid var(--n-800); padding: 24px; background: var(--n-925); display: flex; flex-direction: column; }
.price.feat { border-color: var(--n-600); background: var(--n-900); }
.price .ptier { font-family: var(--font-mono); font-size: 10.5px; letter-spacing: 0.14em; text-transform: uppercase; color: var(--n-500); margin: 0 0 18px; }
.price.feat .ptier { color: var(--n-200); }
.price .pamt { font-size: 30px; font-weight: 500; color: var(--n-100); letter-spacing: -0.02em; }
.price .pper { font-family: var(--font-mono); font-size: 11px; color: var(--n-600); margin-top: 4px; }
.price .pdesc { font-size: 12.5px; line-height: 1.5; color: var(--n-500); margin-top: 16px; }

/* ---- implementation ---- */
.impl { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1px; background: var(--n-880); border: 1px solid var(--n-880); }
.impl .cell { background: var(--n-925); padding: 22px 20px; }
.impl .k { font-size: 11.5px; color: var(--n-500); margin: 0 0 9px; }
.impl .vv { font-family: var(--font-mono); font-size: 14px; color: var(--n-100); }

/* ---- CTA ---- */
.cta-sec { text-align: center; }
.cta-h2 { font-size: clamp(28px, 4vw, 40px); font-weight: var(--head-weight); letter-spacing: var(--head-track); margin: 0 0 14px; }
.cta-h2 .dim { color: var(--n-600); }
.cta-h2 .lit { color: var(--n-050); }
.cta-sub { font-family: var(--font-mono); font-size: 13px; color: var(--n-500); margin: 0 0 30px; }

/* ---- footer ---- */
.foot { border-top: 1px solid var(--n-880); padding: 28px 0; }
.foot-in { display: flex; align-items: center; justify-content: space-between; }
.foot p { font-family: var(--font-mono); font-size: 12px; color: var(--n-600); margin: 0; }
.foot .links { display: flex; gap: 22px; }
.foot .links a { font-family: var(--font-mono); font-size: 12px; color: var(--n-600); transition: color .25s; }
.foot .links a:hover { color: var(--n-300); }

/* ---- live proof demo ---- */
.demo { border: 1px solid var(--n-800); background: var(--n-925); }
.demo-head { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 16px 22px; border-bottom: 1px solid var(--n-880); }
.demo-head .lbl { font-family: var(--font-mono); font-size: 10.5px; letter-spacing: 0.2em; text-transform: uppercase; color: var(--n-500); white-space: nowrap; }
.demo-head .live { font-family: var(--font-mono); font-size: 10.5px; color: var(--n-400); display: flex; align-items: center; gap: 7px; white-space: nowrap; }
.demo-head .dot { width: 6px; height: 6px; border-radius: 50%; background: var(--n-300); animation: pulse 1.8s ease-in-out infinite; }
@keyframes pulse { 0%,100% { opacity: .35; } 50% { opacity: 1; } }

.demo-body { padding: 22px; }
.demo-input-row { display: flex; gap: 10px; align-items: stretch; }
.demo-field {
  flex: 1; background: var(--n-950); border: 1px solid var(--n-800); color: var(--n-100);
  font-family: var(--font-mono); font-size: 13.5px; padding: 13px 15px; outline: none;
  transition: border-color .2s;
}
.demo-field::placeholder { color: var(--n-600); }
.demo-field:focus { border-color: var(--n-600); }
.demo-go {
  font-size: 11px; letter-spacing: 0.16em; text-transform: uppercase; font-weight: 500;
  color: var(--n-950); background: var(--n-100); border: 1px solid var(--n-100);
  padding: 0 22px; white-space: nowrap; transition: background .2s, opacity .2s;
}
.demo-go:hover { background: #fff; }
.demo-go:disabled { opacity: .4; cursor: default; }
.demo-hint { font-family: var(--font-mono); font-size: 11px; color: var(--n-600); margin-top: 11px; }
.demo-hint .drop { color: var(--n-400); border-bottom: 1px dotted var(--n-600); cursor: pointer; }
.demo-hint .drop:hover { color: var(--n-200); }

/* hash line */
.demo-hash { margin-top: 22px; padding-top: 20px; border-top: 1px solid var(--n-880); }
.demo-hash .k { font-family: var(--font-mono); font-size: 10.5px; letter-spacing: 0.14em; text-transform: uppercase; color: var(--n-600); margin: 0 0 8px; }
.demo-hash .hv { font-family: var(--font-mono); font-size: 13px; color: var(--n-100); word-break: break-all; line-height: 1.7; }
.demo-hash .hv .seg { color: var(--n-500); }

/* tiers */
.tiers { margin-top: 22px; display: grid; gap: 1px; background: var(--n-880); border: 1px solid var(--n-880); }
.tier { background: var(--n-900); padding: 16px 18px; display: grid; grid-template-columns: 26px 1fr auto; gap: 14px; align-items: center; }
.tier .tnum { font-family: var(--font-mono); font-size: 11px; color: var(--n-600); }
.tier .tmid .tname { font-size: 14px; color: var(--n-200); font-weight: 500; letter-spacing: -0.01em; }
.tier .tmid .tmeta { font-family: var(--font-mono); font-size: 11.5px; color: var(--n-500); margin-top: 3px; min-height: 15px; }
.tier .tstat { font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.04em; text-transform: uppercase; }
.tier .tstat.idle { color: var(--n-700); }
.tier .tstat.run { color: var(--n-300); }
.tier .tstat.done { color: var(--n-100); }
.tier .tstat.run .spin { display: inline-block; animation: spin 1s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }
.tier.active { background: var(--n-880); }

/* receipt */
.receipt { margin-top: 22px; border: 1px solid var(--n-700); background: var(--n-950); padding: 20px; opacity: 0; transform: translateY(8px); transition: opacity .5s, transform .5s; }
.receipt.show { opacity: 1; transform: none; }
.receipt .rhead { display: flex; align-items: center; justify-content: space-between; margin-bottom: 16px; }
.receipt .rtitle { font-size: 13px; color: var(--n-100); font-weight: 500; white-space: nowrap; }
.receipt .rverified { font-family: var(--font-mono); font-size: 10.5px; letter-spacing: 0.12em; text-transform: uppercase; color: var(--n-950); background: var(--n-100); padding: 4px 9px; }
.receipt .rgrid { display: grid; grid-template-columns: 120px 1fr; gap: 9px 16px; }
.receipt .rk { font-family: var(--font-mono); font-size: 11px; color: var(--n-600); }
.receipt .rv { font-family: var(--font-mono); font-size: 12px; color: var(--n-200); word-break: break-all; }
.dropping { border-color: var(--n-400) !important; }

/* ---- comparison overlay (ported from PricingPage, monotone) ---- */
.cmp-link {
  display: inline-flex; align-items: center; gap: 9px;
  font-family: var(--font-mono); font-size: 12.5px; color: var(--n-500);
  background: transparent; border: 0; padding: 0; margin-top: 30px;
  letter-spacing: 0.02em; cursor: pointer; transition: color .2s;
}
.cmp-link:hover { color: var(--n-100); }
.cmp-link .ar { transition: transform .2s; }
.cmp-link:hover .ar { transform: translateX(3px); }

.cmp-overlay {
  position: fixed; inset: 0; z-index: 200;
  background: color-mix(in srgb, var(--n-950) 84%, transparent);
  backdrop-filter: blur(8px);
  overflow-y: auto; padding: 0 16px 48px;
  animation: cmpFade .22s ease both;
}
@keyframes cmpFade { from { opacity: 0; } to { opacity: 1; } }
.cmp-sheet {
  position: relative; max-width: 1040px; margin: 0 auto; min-height: 100%;
  background: var(--n-950);
  border-left: 1px solid var(--n-850); border-right: 1px solid var(--n-850);
  padding: 0 clamp(20px, 4vw, 56px) 64px;
  animation: cmpRise .3s ease both;
}
@keyframes cmpRise { from { transform: translateY(10px); opacity: 0; } to { transform: none; opacity: 1; } }
.cmp-bar {
  position: sticky; top: 0; z-index: 3;
  display: flex; justify-content: flex-end;
  padding: 16px 0 10px;
  background: linear-gradient(var(--n-950) 72%, transparent);
}
.cmp-close {
  width: 38px; height: 38px; display: flex; align-items: center; justify-content: center;
  background: var(--n-900); border: 1px solid var(--n-700); color: var(--n-300);
  font-size: 13px; transition: border-color .2s, color .2s;
}
.cmp-close:hover { border-color: var(--n-400); color: var(--n-100); }

.cmp-head { padding-bottom: 30px; border-bottom: 1px solid var(--n-800); }
.cmp-eyebrow { font-family: var(--font-mono); font-size: 10.5px; letter-spacing: 0.2em; text-transform: uppercase; color: var(--n-600); margin: 0 0 16px; }
.cmp-h1 { font-size: clamp(28px, 4vw, 42px); font-weight: var(--head-weight); letter-spacing: var(--head-track); color: var(--n-050); margin: 0 0 16px; }
.cmp-lead { font-size: 15px; line-height: 1.6; color: var(--n-400); max-width: 520px; margin: 0; }

.cmp-sub { font-family: var(--font-mono); font-size: 10.5px; letter-spacing: 0.2em; text-transform: uppercase; color: var(--n-600); margin: 0 0 18px; }

.cmp-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; }
.cmp-feat { padding: 32px 0; border-bottom: 1px solid var(--n-800); }
.cmp-colhead { font-family: var(--font-mono); font-size: 10.5px; letter-spacing: 0.14em; text-transform: uppercase; color: var(--n-600); padding: 0 0 12px 18px; border-bottom: 1px solid var(--n-850); }
.cmp-colhead.hl { color: var(--n-200); }
.cmp-rk { font-size: 13.5px; color: var(--n-400); padding: 11px 12px 11px 0; border-bottom: 1px solid var(--n-900); }
.cmp-rc { padding: 11px 18px; border-bottom: 1px solid var(--n-900); border-left: 1px solid var(--n-880); }
.cmp-rc.mid { border-left-color: var(--n-800); }
.cmp-rk.div, .cmp-rc.div { border-top: 1px solid var(--n-850); }
.cmp-cell { font-size: 12px; color: var(--n-500); }
.cmp-cell.hl { color: var(--n-200); }
.cmp-cell.off { color: var(--n-800); }

.cmp-matrix { padding-top: 32px; }
.cmp-mx-head { border-bottom: 1px solid var(--n-800); }
.cmp-mx-head .cmp-sub { margin: 0; padding: 22px 0; align-self: center; }
.cmp-mxh { padding: 22px 0 22px 18px; border-left: 1px solid var(--n-880); }
.cmp-mxh .l { display: block; font-family: var(--font-mono); font-size: 10.5px; letter-spacing: 0.14em; text-transform: uppercase; color: var(--n-600); margin-bottom: 4px; }
.cmp-mxh.hl .l { color: var(--n-200); }
.cmp-mxh .s { display: block; font-family: var(--font-mono); font-size: 10.5px; color: var(--n-700); }
.cmp-mx-row { border-bottom: 1px solid var(--n-900); transition: background .15s; }
.cmp-mx-row:hover { background: var(--n-925); }
.cmp-vid { padding: 26px 24px 26px 0; }
.cmp-vid .vn { font-size: 19px; font-weight: 400; color: var(--n-100); margin: 0 0 6px; letter-spacing: -0.01em; }
.cmp-vid .vt { font-family: var(--font-mono); font-size: 11.5px; color: var(--n-600); line-height: 1.5; margin: 0 0 14px; }
.cmp-vid .vm { font-size: 10px; color: var(--n-700); letter-spacing: 0.04em; margin: 0; }
.cmp-price { padding: 26px 18px; border-left: 1px solid var(--n-880); }
.cmp-price .pa { font-size: 24px; font-weight: 400; color: var(--n-300); margin: 0 0 5px; letter-spacing: -0.02em; }
.cmp-price.mid .pa { color: var(--n-050); }
.cmp-price .pl { font-family: var(--font-mono); font-size: 11px; color: var(--n-600); line-height: 1.5; margin: 0; }

.cmp-notes { display: grid; grid-template-columns: 1fr 1fr; gap: 32px; padding-top: 40px; margin-top: 40px; border-top: 1px solid var(--n-800); }
.cmp-notes .nk { font-family: var(--font-mono); font-size: 10.5px; letter-spacing: 0.2em; text-transform: uppercase; color: var(--n-600); margin: 0 0 12px; }
.cmp-notes .nv { font-size: 13.5px; line-height: 1.6; color: var(--n-500); margin: 0; }
.cmp-notes a { color: var(--n-300); border-bottom: 1px dotted var(--n-600); }
.cmp-notes a:hover { color: var(--n-100); }

@media (max-width: 720px) {
  .cmp-grid { grid-template-columns: 1.5fr 1fr 1fr 1fr; }
  .cmp-colhead { padding-left: 8px; font-size: 9px; letter-spacing: 0.08em; }
  .cmp-rk { font-size: 12px; padding-right: 8px; }
  .cmp-rc { padding: 10px 8px; }
  .cmp-mxh { padding-left: 8px; }
  .cmp-vid { padding-right: 12px; }
  .cmp-vid .vn { font-size: 16px; }
  .cmp-price { padding: 18px 8px; }
  .cmp-price .pa { font-size: 18px; }
  .cmp-notes { grid-template-columns: 1fr; gap: 24px; }
}

/* ---- density: dense ---- */
.shell.dense { --sec-pad: 56px; }
.shell.dense .hero { padding-top: 64px; }
.shell.dense .hero-lead { font-size: 17px; }

@media (max-width: 720px) {
  .wrap { padding-left: 20px; padding-right: 20px; }
  .nav-links a { display: none; }
  .nav-links a:last-of-type { display: inline; }
  .prices { grid-template-columns: 1fr; }
  .impl { grid-template-columns: repeat(2, 1fr); }
}