/* ============================================================
   HRV Dojo — guides
   Static content pages. Same "Signal Dojo" language as the app,
   but laid out for reading rather than for instrumentation.
   ============================================================ */

:root {
  --bg:       #08090B;
  --bg-2:     #0B0D10;
  --panel:    #101418;
  --panel-2:  #0C0F12;
  --panel-hi: #161B21;
  --line:     rgba(255,255,255,0.07);
  --line-2:   rgba(255,255,255,0.12);

  --txt:   #E9EFEC;
  --txt-2: #A3B0B7;
  --txt-3: #6D7981;

  --lime:    #BFFF3C;
  --cyan:    #2FE6D6;
  --amber:   #FFB23D;
  --red:     #FF5B4D;

  /* chart series — validated against the #0B0D10 surface for the
     lightness band, chroma floor, CVD separation and contrast. */
  --s-ref: #78A314;
  --s-dut: #E0347F;

  --sans: "Space Grotesk", ui-sans-serif, system-ui, -apple-system, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, "SF Mono", Menlo, monospace;

  --measure: 68ch;
  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; }
}

body {
  margin: 0;
  /* fill the viewport so the ambient gradients don't stop at a short page's
     content edge and leave a visible seam above the fold */
  min-height: 100vh;
  min-height: 100dvh;
  background:
    radial-gradient(110% 60% at 100% 0%, rgba(47,230,214,.045), transparent 55%),
    radial-gradient(110% 70% at 0% 100%, rgba(191,255,60,.04), transparent 50%),
    var(--bg);
  color: var(--txt);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

.mono { font-family: var(--mono); font-variant-numeric: tabular-nums; }

::selection { background: rgba(191,255,60,.22); }

a { color: var(--lime); text-decoration-color: rgba(191,255,60,.35); text-underline-offset: 3px; }
a:hover { text-decoration-color: var(--lime); }

:focus-visible {
  outline: 2px solid var(--lime);
  outline-offset: 3px;
  border-radius: 4px;
}

.skip {
  position: absolute;
  left: -9999px;
}
.skip:focus {
  left: 12px; top: 12px;
  z-index: 20;
  background: var(--panel-hi);
  padding: 10px 16px;
  border-radius: 10px;
  border: 1px solid var(--line-2);
}

/* ---- shell ---- */
.wrap {
  max-width: 860px;
  margin: 0 auto;
  padding: 0 24px;
}

.topbar {
  border-bottom: 1px solid var(--line);
  background: rgba(8,9,11,.82);
  backdrop-filter: blur(10px);
  position: sticky; top: 0; z-index: 10;
}
.topbar .wrap {
  display: flex; align-items: center; gap: 18px;
  height: 62px;
}
.brand {
  display: flex; align-items: center; gap: 10px;
  font-weight: 700; letter-spacing: -.01em;
  color: var(--txt); text-decoration: none;
  font-size: 16px;
}
.brand svg { width: 22px; height: 22px; display: block; }
.brand b { color: var(--lime); font-weight: 700; }
.topbar nav { margin-left: auto; display: flex; gap: 20px; align-items: center; }
.topbar nav a {
  font-size: 14px; color: var(--txt-2); text-decoration: none; font-weight: 500;
}
.topbar nav a:hover { color: var(--txt); }
.topbar nav a.cta {
  color: var(--bg); background: var(--lime);
  padding: 7px 15px; border-radius: 999px; font-weight: 600;
}
.topbar nav a.cta:hover { color: var(--bg); filter: brightness(1.08); }

/* ---- article ---- */
main { padding: 56px 0 24px; }

.crumb {
  font-size: 13px; color: var(--txt-3);
  font-family: var(--mono);
  letter-spacing: .04em; text-transform: uppercase;
  margin-bottom: 18px;
}
.crumb a { color: var(--txt-3); text-decoration: none; }
.crumb a:hover { color: var(--txt-2); }

h1 {
  font-size: clamp(34px, 5.2vw, 48px);
  line-height: 1.08;
  letter-spacing: -.028em;
  font-weight: 700;
  margin: 0 0 20px;
  max-width: 20ch;
}
.standfirst {
  font-size: 20px;
  line-height: 1.55;
  color: var(--txt-2);
  margin: 0 0 26px;
  max-width: var(--measure);
}
.byline {
  font-family: var(--mono);
  font-size: 12.5px;
  color: var(--txt-3);
  letter-spacing: .03em;
  padding-bottom: 30px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 40px;
}

article { max-width: var(--measure); }
article > * { max-width: var(--measure); }

h2 {
  font-size: 27px; line-height: 1.2; letter-spacing: -.02em;
  font-weight: 700;
  margin: 56px 0 16px;
  scroll-margin-top: 80px;
}
h3 {
  font-size: 19px; line-height: 1.3; letter-spacing: -.01em;
  font-weight: 600;
  margin: 34px 0 10px;
  color: var(--txt);
}
p { margin: 0 0 18px; }
strong { color: var(--txt); font-weight: 600; }
em { color: var(--txt); }

ul, ol { margin: 0 0 18px; padding-left: 22px; }
li { margin-bottom: 9px; }
li::marker { color: var(--txt-3); }

code {
  font-family: var(--mono);
  font-size: .88em;
  background: var(--panel-hi);
  border: 1px solid var(--line);
  border-radius: 5px;
  padding: 1px 5px;
  color: var(--txt);
}

hr { border: 0; border-top: 1px solid var(--line); margin: 48px 0; }

/* ---- TOC ---- */
.toc {
  background: var(--panel-2);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 20px 24px;
  margin: 0 0 44px;
}
.toc h2 {
  font-size: 11px; letter-spacing: .12em; text-transform: uppercase;
  color: var(--txt-3); font-family: var(--mono); font-weight: 500;
  margin: 0 0 12px;
}
.toc ol { margin: 0; padding-left: 20px; }
.toc li { margin-bottom: 6px; font-size: 15px; }
.toc a { color: var(--txt-2); text-decoration: none; }
.toc a:hover { color: var(--lime); }

/* ---- callout ---- */
.note {
  border-left: 2px solid var(--cyan);
  background: linear-gradient(90deg, rgba(47,230,214,.055), transparent 70%);
  padding: 16px 20px;
  border-radius: 0 10px 10px 0;
  margin: 28px 0;
  font-size: 15.5px;
  color: var(--txt-2);
}
.note.warn {
  border-left-color: var(--amber);
  background: linear-gradient(90deg, rgba(255,178,61,.06), transparent 70%);
}
.note b { color: var(--txt); }
.note > :last-child { margin-bottom: 0; }

/* ---- steps ---- */
.steps { counter-reset: s; list-style: none; padding: 0; margin: 30px 0 0; }
.steps > li {
  counter-increment: s;
  position: relative;
  padding: 0 0 30px 54px;
  margin: 0;
  border-left: 1px solid var(--line-2);
  margin-left: 17px;
}
.steps > li:last-child { border-left-color: transparent; padding-bottom: 6px; }
.steps > li::before {
  content: counter(s);
  position: absolute; left: -18px; top: -3px;
  width: 35px; height: 35px;
  border-radius: 50%;
  background: var(--panel-hi);
  border: 1px solid var(--line-2);
  color: var(--lime);
  font-family: var(--mono); font-size: 14px; font-weight: 600;
  display: grid; place-items: center;
}
.steps h3 { margin: 4px 0 8px; }
.steps > li > :last-child { margin-bottom: 0; }

/* ---- verdict / stat tiles ---- */
.tiles {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(158px, 1fr));
  gap: 12px;
  margin: 30px 0;
}
.tile {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 13px;
  padding: 16px 18px;
}
.tile .k {
  font-family: var(--mono); font-size: 10.5px; letter-spacing: .1em;
  text-transform: uppercase; color: var(--txt-3);
  margin-bottom: 8px;
}
.tile .v {
  font-family: var(--mono); font-size: 27px; font-weight: 600;
  letter-spacing: -.02em; line-height: 1.1;
}
.tile .u { font-size: 14px; color: var(--txt-3); font-weight: 400; }
.tile .s { font-size: 13px; color: var(--txt-3); margin-top: 6px; line-height: 1.4; }
.tile.good .v { color: var(--lime); }
.tile.bad  .v { color: var(--red); }

/* ---- figures & charts ---- */
figure {
  margin: 36px 0;
  max-width: none;
  width: 100%;
}
.chart {
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 20px 20px 14px;
}
.chart-head { margin-bottom: 4px; }
.chart-title { font-size: 15px; font-weight: 600; letter-spacing: -.01em; }
.chart-sub { font-size: 13px; color: var(--txt-3); margin-top: 2px; }
.chart-scroll { overflow-x: auto; }
.chart svg { display: block; width: 100%; height: auto; min-width: 460px; }

svg .g { stroke: rgba(255,255,255,.055); stroke-width: 1; }
svg .ax {
  font-family: var(--mono); font-size: 11px; fill: var(--txt-3);
}
svg .ln { fill: none; stroke-width: 2; stroke-linejoin: round; stroke-linecap: round; }
svg .ln.ref { stroke: var(--s-ref); }
svg .ln.dut { stroke: var(--s-dut); }
svg .dlab { font-family: var(--mono); font-size: 11.5px; font-weight: 600; }

.legend {
  display: flex; gap: 20px; flex-wrap: wrap;
  font-size: 13px; color: var(--txt-2);
  margin-top: 12px;
}
.legend span { display: inline-flex; align-items: center; gap: 8px; }
.legend i {
  width: 13px; height: 3px; border-radius: 2px; display: block;
}

figcaption {
  font-size: 13.5px; color: var(--txt-3); line-height: 1.5;
  margin-top: 12px;
}

/* crosshair layer */
.xh { stroke: var(--line-2); stroke-width: 1; pointer-events: none; opacity: 0; }
.xh-dot { stroke: var(--bg-2); stroke-width: 2; pointer-events: none; opacity: 0; }
.chart.live .xh, .chart.live .xh-dot { opacity: 1; }

.tip {
  position: absolute;
  pointer-events: none;
  background: var(--panel-hi);
  border: 1px solid var(--line-2);
  border-radius: 9px;
  padding: 9px 12px;
  font-size: 13px;
  line-height: 1.5;
  white-space: nowrap;
  opacity: 0;
  transition: opacity .1s;
  z-index: 4;
  box-shadow: 0 8px 24px rgba(0,0,0,.5);
}
.tip.on { opacity: 1; }
.tip .tt { font-family: var(--mono); color: var(--txt-3); font-size: 11px; margin-bottom: 4px; }
.tip .tr { display: flex; align-items: center; gap: 8px; }
.tip .tr i { width: 9px; height: 9px; border-radius: 2px; display: block; flex: none; }
.tip .tr b { font-family: var(--mono); margin-left: auto; padding-left: 14px; font-weight: 600; }
.plot-wrap { position: relative; }

/* ---- bar rows (single-measure magnitude) ---- */
.bars { margin: 26px 0; display: grid; gap: 10px; }
.bar-row {
  display: grid;
  grid-template-columns: minmax(94px, auto) 1fr auto;
  align-items: center;
  gap: 14px;
  font-size: 14px;
}
.bar-row .lab { color: var(--txt-2); }
.bar-track {
  height: 12px;
  background: var(--panel-hi);
  border-radius: 4px;
  overflow: hidden;
}
.bar-fill { height: 100%; border-radius: 4px; display: block; }
.bar-row .val { font-family: var(--mono); font-size: 14px; font-weight: 600; }

/* ---- table ---- */
.tbl-scroll { overflow-x: auto; margin: 26px 0; }
table {
  border-collapse: collapse;
  width: 100%;
  min-width: 440px;
  font-size: 14.5px;
}
caption {
  text-align: left;
  font-size: 13px;
  color: var(--txt-3);
  padding-bottom: 10px;
}
th, td {
  text-align: left;
  padding: 11px 14px;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
}
thead th {
  font-family: var(--mono); font-size: 11px; letter-spacing: .08em;
  text-transform: uppercase; color: var(--txt-3); font-weight: 500;
  border-bottom-color: var(--line-2);
}
td.n, th.n { text-align: right; font-family: var(--mono); font-variant-numeric: tabular-nums; }
tbody tr:last-child td { border-bottom: 0; }
td b { color: var(--txt); }

/* ---- FAQ ---- */
.faq { margin: 26px 0; }
.faq details {
  border-bottom: 1px solid var(--line);
}
.faq summary {
  cursor: pointer;
  padding: 17px 30px 17px 0;
  font-weight: 600;
  font-size: 16.5px;
  list-style: none;
  position: relative;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+";
  position: absolute; right: 4px; top: 50%; transform: translateY(-50%);
  color: var(--txt-3); font-family: var(--mono); font-size: 19px; font-weight: 400;
}
.faq details[open] summary::after { content: "−"; }
.faq summary:hover { color: var(--lime); }
.faq .a { padding: 0 0 18px; color: var(--txt-2); font-size: 15.5px; }
.faq .a > :last-child { margin-bottom: 0; }

/* ---- guide cards (hub) ---- */
.cards { display: grid; gap: 14px; margin: 36px 0 0; max-width: none; }
.card {
  display: block;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 15px;
  padding: 24px 26px;
  text-decoration: none;
  color: inherit;
  transition: border-color .15s, background .15s;
}
.card:hover { border-color: var(--line-2); background: var(--panel-hi); }
.card .kick {
  font-family: var(--mono); font-size: 10.5px; letter-spacing: .11em;
  text-transform: uppercase; color: var(--lime); margin-bottom: 10px;
}
.card h2 { font-size: 21px; margin: 0 0 8px; letter-spacing: -.015em; }
.card p { color: var(--txt-2); font-size: 15px; margin: 0; }

/* ---- CTA ---- */
.cta-box {
  background: var(--panel);
  border: 1px solid var(--line-2);
  border-radius: 16px;
  padding: 30px 32px;
  margin: 56px 0 0;
  max-width: none;
}
.cta-box h2 { margin: 0 0 10px; font-size: 22px; }
.cta-box p { color: var(--txt-2); font-size: 15.5px; margin: 0 0 20px; max-width: 56ch; }
.btn {
  display: inline-block;
  background: var(--lime); color: var(--bg);
  font-weight: 600; font-size: 15px;
  padding: 11px 22px; border-radius: 999px;
  text-decoration: none;
}
.btn:hover { color: var(--bg); filter: brightness(1.08); }
.btn.ghost {
  background: transparent; color: var(--txt);
  border: 1px solid var(--line-2);
  margin-left: 8px;
}
.btn.ghost:hover { background: var(--panel-hi); color: var(--txt); }

/* ---- related ---- */
.related { margin-top: 56px; max-width: none; }
.related h2 { font-size: 13px; letter-spacing: .1em; text-transform: uppercase; color: var(--txt-3); font-family: var(--mono); font-weight: 500; margin-bottom: 16px; }

/* ---- footer ---- */
footer {
  border-top: 1px solid var(--line);
  margin-top: 72px;
  padding: 32px 0 56px;
  font-size: 13.5px;
  color: var(--txt-3);
}
footer .wrap { display: flex; gap: 20px; flex-wrap: wrap; align-items: baseline; }
footer nav { display: flex; gap: 18px; margin-left: auto; flex-wrap: wrap; }
footer a { color: var(--txt-3); text-decoration: none; }
footer a:hover { color: var(--txt-2); }
.disclaimer {
  margin-top: 18px;
  font-size: 12.5px;
  line-height: 1.55;
  color: #59646B;
  max-width: 70ch;
}

@media (max-width: 640px) {
  body { font-size: 16px; }
  main { padding-top: 36px; }
  .wrap { padding: 0 18px; }
  h2 { font-size: 23px; margin-top: 44px; }
  .standfirst { font-size: 18px; }
  .topbar nav a:not(.cta) { display: none; }
  .cta-box, .chart { padding-left: 18px; padding-right: 18px; }
  .steps > li { padding-left: 42px; }
}