/* Body Signals landing page. No external fonts, no frameworks.
   Palette validated for colour-vision deficiency (coral = signal, teal = your normal) in both themes. */
:root {
  --paper: #F3EEE4; --paper-2: #EAE3D6; --card: #FBF8F2; --ink: #17181C; --ink-2: #4A4C55; --ink-3: #777986;
  --rule: #DCD4C5; --grid: #E4DDD0;
  --signal: #D9442B; --signal-soft: rgba(217, 68, 43, .14);
  --normal: #0E8A74; --normal-band: rgba(14, 138, 116, .16); --normal-edge: rgba(14, 138, 116, .55);
  --pop: #6F6B7E; --pop-band: rgba(111, 107, 126, .10);
  --ecg: rgba(217, 68, 43, .07);
  --shadow: 0 1px 0 rgba(23, 24, 28, .04), 0 12px 32px -18px rgba(23, 24, 28, .25);
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, "Book Antiqua", Georgia, "Times New Roman", serif;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
  --r: 18px;
  color-scheme: light;
}
:root[data-theme="dark"] {
  --paper: #0C0F13; --paper-2: #12161C; --card: #151A21; --ink: #ECE7DD; --ink-2: #B9B6AE; --ink-3: #8A8C93;
  --rule: #252B34; --grid: #1E242C;
  --signal: #E85A3E; --signal-soft: rgba(232, 90, 62, .18);
  --normal: #22A887; --normal-band: rgba(34, 168, 135, .18); --normal-edge: rgba(34, 168, 135, .6);
  --pop: #9894A8; --pop-band: rgba(152, 148, 168, .12);
  --ecg: rgba(232, 90, 62, .06);
  --shadow: 0 1px 0 rgba(0, 0, 0, .3), 0 18px 40px -20px rgba(0, 0, 0, .7);
  color-scheme: dark;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } *, *::before, *::after { animation: none !important; transition: none !important; } }
body { margin: 0; background: var(--paper); color: var(--ink); font: 17px/1.6 var(--sans); }
a { color: inherit; }
:focus-visible { outline: 2.5px solid var(--signal); outline-offset: 3px; border-radius: 6px; }
.skip { position: absolute; left: -999px; top: 8px; background: var(--ink); color: var(--paper); padding: 8px 14px; border-radius: 8px; z-index: 10; }
.skip:focus { left: 12px; }

/* ---------- header */
.top { position: sticky; top: 0; z-index: 5; display: flex; align-items: center; gap: 24px; padding: 14px clamp(18px, 4vw, 48px);
  background: color-mix(in srgb, var(--paper) 86%, transparent); backdrop-filter: saturate(1.4) blur(10px); -webkit-backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid color-mix(in srgb, var(--rule) 70%, transparent); }
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; font: 600 18px/1 var(--serif); letter-spacing: .01em; }
.mark { width: 30px; height: 30px; }
.mark-band { fill: var(--normal-band); stroke: var(--normal-edge); stroke-width: 1; }
.mark-line { fill: none; stroke: var(--signal); stroke-width: 2.4; stroke-linecap: round; stroke-linejoin: round;
  stroke-dasharray: 60; animation: trace 3.2s ease-in-out infinite; }
@keyframes trace { 0% { stroke-dashoffset: 60; } 45%, 70% { stroke-dashoffset: 0; } 100% { stroke-dashoffset: -60; } }
.top nav { display: flex; gap: 22px; margin-left: auto; font-size: 15px; }
.top nav a { text-decoration: none; color: var(--ink-2); }
.top nav a:hover { color: var(--ink); }
.theme { width: 40px; height: 40px; border-radius: 50%; border: 1px solid var(--rule); background: var(--card); color: var(--ink); cursor: pointer; display: grid; place-items: center; }
.theme svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; }
:root[data-theme="dark"] .theme circle { fill: currentColor; }
@media (max-width: 760px) { .top nav { display: none; } .theme { margin-left: auto; } }

/* ---------- layout */
main { overflow-x: clip; }
.block { max-width: 1120px; margin: 0 auto; padding: clamp(64px, 10vw, 120px) clamp(18px, 4vw, 48px) 0; }
.kicker { font: 500 13px/1 var(--mono); letter-spacing: .08em; text-transform: uppercase; color: var(--signal); margin: 0 0 14px; }
h1, h2, h3 { font-family: var(--serif); font-weight: 600; letter-spacing: -.01em; margin: 0; }
h2 { font-size: clamp(30px, 4.6vw, 50px); line-height: 1.08; max-width: 20ch; }
h3 { font-size: 21px; line-height: 1.25; }
.sub { color: var(--ink-2); max-width: 66ch; margin: 18px 0 0; }
.note { color: var(--ink-3); font-size: 14.5px; max-width: 80ch; margin-top: 18px; }

/* ---------- hero */
.hero { position: relative; max-width: 1240px; margin: 0 auto; padding: clamp(40px, 8vw, 96px) clamp(18px, 4vw, 48px) 0;
  display: grid; grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr); gap: clamp(28px, 5vw, 64px); align-items: center; }
.hero::before { content: ""; position: absolute; inset: 0 -50vw; z-index: -1; pointer-events: none;
  background-image: linear-gradient(var(--ecg) 1px, transparent 1px), linear-gradient(90deg, var(--ecg) 1px, transparent 1px);
  background-size: 28px 28px; mask-image: linear-gradient(to bottom, #000 40%, transparent); -webkit-mask-image: linear-gradient(to bottom, #000 40%, transparent); }
.eyebrow { font: 500 13px/1.3 var(--mono); letter-spacing: .06em; text-transform: uppercase; color: var(--ink-3); margin: 0 0 18px; }
h1 { font-size: clamp(46px, 7.6vw, 92px); line-height: .98; letter-spacing: -.025em; }
h1 em { font-style: italic; color: var(--normal); }
.lede { font-size: clamp(17px, 1.6vw, 20px); color: var(--ink-2); max-width: 54ch; margin: 24px 0 0; }
.lede strong { color: var(--ink); }
.cta { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 30px; }
.btn { display: inline-flex; align-items: center; gap: 8px; padding: 13px 20px; border-radius: 999px; font: 600 15px/1 var(--sans);
  text-decoration: none; border: 1px solid var(--ink); cursor: pointer; background: transparent; color: var(--ink); transition: transform .15s ease, background .15s ease; }
.btn:hover { transform: translateY(-1px); }
.btn.primary { background: var(--ink); color: var(--paper); }
.btn.small { padding: 9px 14px; font-size: 14px; border-color: var(--rule); background: var(--card); }
.hero-facts { list-style: none; padding: 0; margin: 34px 0 0; display: flex; flex-wrap: wrap; gap: 8px 22px; font-size: 14px; color: var(--ink-3); }
.hero-facts b { color: var(--ink); font-family: var(--mono); }
.hero-viz { margin: 0; background: var(--card); border: 1px solid var(--rule); border-radius: var(--r); box-shadow: var(--shadow); padding: 14px 14px 12px; }
#hero-chart { width: 100%; height: clamp(220px, 30vw, 340px); display: block; }
.hero-viz figcaption { font-size: 13px; color: var(--ink-3); margin-top: 8px; }
.tag { font: 600 10.5px/1 var(--mono); text-transform: uppercase; letter-spacing: .08em; color: var(--signal); border: 1px solid currentColor; border-radius: 4px; padding: 3px 5px; margin-right: 6px; vertical-align: 1px; }
@media (max-width: 880px) { .hero { grid-template-columns: 1fr; } }

/* hero chart marks */
.h-band { fill: var(--normal-band); }
.h-edge { fill: none; stroke: var(--normal-edge); stroke-width: 1; stroke-dasharray: 3 4; }
.h-line { fill: none; stroke: var(--ink); stroke-width: 2; stroke-linejoin: round; stroke-linecap: round; opacity: .85; }
.h-draw { stroke-dasharray: var(--len); stroke-dashoffset: var(--len); animation: draw 4.5s cubic-bezier(.4, 0, .2, 1) forwards; }
@keyframes draw { to { stroke-dashoffset: 0; } }
.h-out { fill: var(--signal); stroke: var(--card); stroke-width: 2; opacity: 0; animation: pop .4s ease forwards; }
@keyframes pop { from { opacity: 0; transform: scale(.4); } to { opacity: 1; transform: scale(1); } }
.h-out { transform-box: fill-box; transform-origin: center; }
.h-lbl { font: 600 12px var(--mono); fill: var(--normal); }
.h-lbl.sig { fill: var(--signal); }

/* ---------- problem / approach */
.cols3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; margin-top: 40px; }
.cols2 { display: grid; grid-template-columns: 1fr 1fr; gap: 0 36px; margin-top: 32px; }
@media (max-width: 860px) { .cols3, .cols2 { grid-template-columns: 1fr; } }
.pcard { background: var(--card); border: 1px solid var(--rule); border-radius: var(--r); padding: 26px; position: relative; overflow: hidden; }
.pcard::after { content: ""; position: absolute; left: 26px; right: 26px; top: 0; height: 3px; background: var(--signal); border-radius: 0 0 3px 3px; opacity: .8; }
.pcard p { color: var(--ink-2); margin: 10px 0 0; }
.rules { list-style: none; padding: 0; margin: 40px 0 0; display: grid; gap: 0; }
.rules li { display: grid; grid-template-columns: 90px 1fr; gap: 20px; padding: 28px 0; border-top: 1px solid var(--rule); }
.rules li:last-child { border-bottom: 1px solid var(--rule); }
.rule-n { font: italic 600 46px/1 var(--serif); color: var(--normal); }
.rules p { color: var(--ink-2); margin: 8px 0 0; max-width: 70ch; }
@media (max-width: 600px) { .rules li { grid-template-columns: 54px 1fr; } .rule-n { font-size: 34px; } }

/* ---------- demo panels */
.panel { margin-top: 32px; background: var(--card); border: 1px solid var(--rule); border-radius: var(--r); box-shadow: var(--shadow); padding: clamp(16px, 2.4vw, 26px); }
.controls { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; justify-content: space-between; }
.seg { display: inline-flex; padding: 4px; background: var(--paper-2); border-radius: 999px; border: 1px solid var(--rule); }
.seg button { border: 0; background: transparent; color: var(--ink-2); font: 600 14px/1 var(--sans); padding: 10px 16px; border-radius: 999px; cursor: pointer; }
.seg button.on { background: var(--card); color: var(--ink); box-shadow: 0 1px 3px rgba(0, 0, 0, .12); }
.readout, .act-read { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin: 20px 0 6px; }
.readout > div, .act-read > div { padding: 12px 14px; border-radius: 12px; background: var(--paper-2); }
.big { display: block; font: 600 clamp(26px, 3.4vw, 36px)/1.05 var(--mono); letter-spacing: -.02em; font-variant-numeric: tabular-nums; }
.lbl { display: block; font-size: 13px; color: var(--ink-3); margin-top: 6px; line-height: 1.35; }
@media (max-width: 640px) { .readout, .act-read { grid-template-columns: 1fr; } }
.chart-wrap { position: relative; margin-top: 10px; }
.chart { width: 100%; height: clamp(260px, 34vw, 380px); display: block; touch-action: pan-y; }
.chart .grid { stroke: var(--grid); stroke-width: 1; }
.chart .axis { fill: var(--ink-3); font: 11.5px var(--mono); }
.chart .band-personal { fill: var(--normal-band); }
.chart .edge-personal { fill: none; stroke: var(--normal-edge); stroke-width: 1.2; }
.chart .band-pop { fill: var(--pop-band); }
.chart .edge-pop { fill: none; stroke: var(--pop); stroke-width: 1.2; stroke-dasharray: 6 5; }
.chart .line { fill: none; stroke: var(--ink); stroke-width: 2; stroke-linejoin: round; stroke-linecap: round; opacity: .8; }
.chart .out { fill: var(--signal); stroke: var(--card); stroke-width: 2; }
.chart .streak { fill: var(--signal-soft); }
.chart .plant { stroke: var(--ink-3); stroke-dasharray: 2 4; }
.chart .plant-t { fill: var(--ink-3); font: 11px var(--mono); }
.chart .cross { stroke: var(--ink-3); stroke-dasharray: 3 3; }
.chart .hot { fill: var(--ink); stroke: var(--card); stroke-width: 2; }
.chart .band-t { font: 600 11.5px var(--mono); }
.chart .band-t.personal { fill: var(--normal); }
.chart .band-t.pop { fill: var(--pop); }
.tip { position: absolute; pointer-events: none; background: var(--ink); color: var(--paper); font: 12.5px/1.4 var(--mono); padding: 8px 10px; border-radius: 8px; white-space: nowrap; transform: translate(-50%, calc(-100% - 12px)); z-index: 2; }
.legend { display: flex; flex-wrap: wrap; gap: 8px 20px; font-size: 13px; color: var(--ink-2); margin-top: 10px; }
.legend i { display: inline-block; width: 18px; height: 10px; margin-right: 7px; border-radius: 3px; vertical-align: -1px; }
.legend b { font-weight: 500; }
.lg-line { height: 2px !important; background: var(--ink); opacity: .8; vertical-align: 3px !important; }
.lg-band { background: var(--normal-band); border: 1px solid var(--normal-edge); }
.legend.pop .lg-band { background: var(--pop-band); border: 1px dashed var(--pop); }
.lg-out { width: 10px !important; height: 10px !important; border-radius: 50% !important; background: var(--signal); }
.lg-streak { background: var(--signal-soft); }
.table-view { margin-top: 14px; font-size: 14px; }
.table-view summary { cursor: pointer; color: var(--ink-2); }
.tbl-scroll { overflow-x: auto; }
.table-view table { border-collapse: collapse; margin-top: 10px; font: 13px var(--mono); min-width: 520px; }
.table-view caption { text-align: left; color: var(--ink-3); padding-bottom: 6px; font-family: var(--sans); }
.table-view th, .table-view td { padding: 5px 12px 5px 0; border-bottom: 1px solid var(--rule); text-align: right; }
.table-view th:first-child, .table-view td:first-child { text-align: left; }

/* actogram */
.act { display: grid; grid-template-columns: minmax(240px, 320px) 1fr; gap: 26px; align-items: start; }
@media (max-width: 860px) { .act { grid-template-columns: 1fr; } }
.act-controls label { display: flex; justify-content: space-between; font-size: 14px; color: var(--ink-2); margin-top: 10px; }
.act-controls output { font: 600 14px var(--mono); color: var(--ink); }
.act-read { grid-template-columns: 1fr; margin-top: 20px; }
input[type="range"] { width: 100%; accent-color: var(--normal); height: 28px; }
.acto { width: 100%; height: auto; display: block; }
.acto .row-bg { fill: var(--paper-2); }
.acto .sl { fill: var(--normal); }
.acto .sl.we { fill: var(--signal); }
.acto .axis { fill: var(--ink-3); font: 11px var(--mono); }
.acto .mid { stroke: var(--grid); }

/* ---------- architecture flow */
.flow { list-style: none; padding: 0; margin: 40px 0 0; display: grid; grid-template-columns: repeat(6, 1fr); gap: 14px; counter-reset: f; position: relative; }
.flow li { position: relative; background: var(--card); border: 1px solid var(--rule); border-radius: 14px; padding: 18px 16px 18px; display: flex; flex-direction: column; gap: 6px; }
.flow li b { font: 600 17px/1.2 var(--serif); }
.flow li span:last-child { font-size: 13.5px; color: var(--ink-2); line-height: 1.45; }
.node-k { font: 500 11px/1 var(--mono); text-transform: uppercase; letter-spacing: .08em; color: var(--normal); }
.flow li:not(:last-child)::after { content: ""; position: absolute; top: 50%; right: -14px; width: 14px; height: 2px; background: var(--rule); }
.flow li:not(:last-child)::before { content: ""; position: absolute; top: calc(50% - 3px); right: -11px; width: 8px; height: 8px; border-radius: 50%; background: var(--signal); z-index: 1;
  animation: hop 2.4s ease-in-out infinite; animation-delay: calc(var(--i, 0) * .4s); }
@keyframes hop { 0%, 100% { opacity: .15; transform: translateX(-6px); } 50% { opacity: 1; transform: translateX(4px); } }
.flow li:last-child { border-color: var(--normal-edge); background: color-mix(in srgb, var(--normal-band) 60%, var(--card)); }
@media (max-width: 1000px) {
  .flow { grid-template-columns: 1fr; gap: 14px; }
  .flow li { flex-direction: row; flex-wrap: wrap; align-items: baseline; column-gap: 12px; }
  .flow li span:last-child { flex-basis: 100%; }
  .flow li:not(:last-child)::after { top: auto; bottom: -14px; right: auto; left: 32px; width: 2px; height: 14px; }
  .flow li:not(:last-child)::before { top: auto; bottom: -11px; right: auto; left: 29px; }
  @keyframes hop { 0%, 100% { opacity: .15; transform: translateY(-6px); } 50% { opacity: 1; transform: translateY(4px); } }
}

/* ---------- engine */
.engine { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin-top: 40px; }
@media (max-width: 1000px) { .engine { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px) { .engine { grid-template-columns: 1fr; } }
.ecard { background: var(--card); border: 1px solid var(--rule); border-radius: 16px; padding: 18px 18px 16px; display: flex; flex-direction: column; }
.ecard .glyph { width: 100%; height: 54px; margin-bottom: 12px; }
.ecard .glyph .gb { fill: var(--normal-band); }
.ecard .glyph .gl { fill: none; stroke: var(--ink); stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; opacity: .85; }
.ecard .glyph .gs { fill: var(--signal); }
.ecard .glyph .gsl { fill: none; stroke: var(--signal); stroke-width: 1.8; stroke-dasharray: 3 3; }
.ecard .glyph .gn { fill: var(--normal); }
.ecard h3 { font-size: 19px; }
.ecard p { font-size: 14.5px; color: var(--ink-2); margin: 8px 0 0; }
.ecard .quiet { margin-top: auto; padding-top: 12px; font-size: 13.5px; color: var(--ink-3); }
.ecard .quiet b { color: var(--normal); font-weight: 600; }

/* ---------- validation */
.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1px; margin-top: 36px; background: var(--rule); border: 1px solid var(--rule); border-radius: var(--r); overflow: hidden; }
@media (max-width: 1000px) { .stats { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 520px) { .stats { grid-template-columns: 1fr; } }
.stat { background: var(--card); padding: 24px 22px; }
.stat .v { display: block; font: 600 clamp(30px, 3.6vw, 40px)/1 var(--mono); letter-spacing: -.03em; font-variant-numeric: tabular-nums; }
.stat .v small { font-size: .5em; color: var(--ink-3); letter-spacing: 0; }
.stat .k { display: block; font-size: 14px; color: var(--ink-2); margin-top: 10px; line-height: 1.45; }

/* ---------- privacy / stack */
.checks { list-style: none; padding: 0; margin: 0; }
.checks li { position: relative; padding: 16px 0 16px 34px; border-top: 1px solid var(--rule); color: var(--ink-2); }
.checks li b { color: var(--ink); }
.checks li::before { content: ""; position: absolute; left: 2px; top: 21px; width: 16px; height: 9px; border-left: 2.5px solid var(--normal); border-bottom: 2.5px solid var(--normal); transform: rotate(-45deg); }
.pills { list-style: none; padding: 0; margin: 28px 0 0; display: flex; flex-wrap: wrap; gap: 10px; }
.pills li { font: 500 14px/1 var(--mono); padding: 11px 15px; border: 1px solid var(--rule); border-radius: 999px; background: var(--card); }

/* ---------- footer */
.foot { max-width: 1120px; margin: clamp(80px, 10vw, 130px) auto 0; padding: 30px clamp(18px, 4vw, 48px) 50px; border-top: 1px solid var(--rule); color: var(--ink-3); font-size: 14px; }
.foot p { margin: 4px 0; }
.foot b { color: var(--ink); font-family: var(--serif); }

@media (forced-colors: active) {
  .chart .out, .lg-out { forced-color-adjust: none; }
  .chart .band-personal, .chart .band-pop { stroke: CanvasText; }
}