/* ==========================================================================
   THALAMUS — design tokens
   Palette: cool clinical paper, ink navy, steel-slate structure, sparse
   deep-signal red for flags. No warm cream, no terracotta, no near-black
   acid-accent defaults.
   Type: Space Grotesk (display — technical, geometric, a little unusual),
         IBM Plex Sans (body — built for technical/engineering communication),
         IBM Plex Mono (utility — layer labels, tags, provenance, data)
   ========================================================================== */

:root{
  --ink:        #12181F;
  --ink-soft:   #29323C;
  --paper:      #F4F5F1;
  --paper-dim:  #E9EAE4;
  --steel:      #3B5166;
  --steel-light:#6E8899;
  --signal:     #9B3A3A;
  --mist:       #6B7680;
  --line:       #D8DAD3;
  --line-dark:  #33404C;

  --font-display: 'Space Grotesk', 'Arial Narrow', sans-serif;
  --font-body:    'IBM Plex Sans', -apple-system, sans-serif;
  --font-mono:    'IBM Plex Mono', 'Courier New', monospace;

  --max: 1120px;
  --pad: clamp(20px, 5vw, 64px);
}

*{ box-sizing: border-box; }
html{ scroll-behavior: smooth; }

body{
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

img, svg{ max-width: 100%; display: block; }

a{ color: inherit; }

:focus-visible{
  outline: 2px solid var(--signal);
  outline-offset: 3px;
}

h1, h2, h3, h4{
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.1;
  margin: 0;
  letter-spacing: -0.01em;
}

p{ margin: 0; }

.wrap{
  max-width: var(--max);
  margin: 0 auto;
  padding-left: var(--pad);
  padding-right: var(--pad);
}

.eyebrow{
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--steel);
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 16px;
}
.eyebrow::before{
  content: "";
  width: 18px;
  height: 1px;
  background: var(--steel);
  display: inline-block;
}

/* ---------------------------------- nav --------------------------------- */

.site-nav{
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(244,245,241,0.92);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--line);
}
.site-nav .wrap{
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}
.logo{
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 18px;
  letter-spacing: 0.02em;
  text-decoration: none;
  color: var(--ink);
  display: flex;
  align-items: center;
  gap: 9px;
}
.logo .mark{
  width: 20px; height: 20px;
  flex: none;
}
.logo .mark circle{ fill: none; stroke: var(--steel); stroke-width: 1.4; }
.logo .mark circle.c2{ stroke: var(--signal); }

.nav-links{
  display: flex;
  align-items: center;
  gap: 36px;
  list-style: none;
  margin: 0; padding: 0;
}
.nav-links a{
  text-decoration: none;
  font-size: 14px;
  color: var(--ink-soft);
  position: relative;
  padding: 4px 0;
}
.nav-links a:hover{ color: var(--ink); }
.nav-links a[aria-current="page"]{ color: var(--ink); }
.nav-links a[aria-current="page"]::after{
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: -2px;
  height: 2px;
  background: var(--signal);
}
.nav-cta{ display: flex; align-items: center; gap: 24px; }
.nav-toggle{ display: none; }

/* --------------------------------- buttons -------------------------------- */

.btn{
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 500;
  text-decoration: none;
  padding: 12px 22px;
  border-radius: 3px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}
.btn-primary{
  background: var(--ink);
  color: var(--paper);
}
.btn-primary:hover{ background: var(--steel); }
.btn-ghost{
  background: transparent;
  border-color: var(--line-dark);
  color: var(--ink);
}
.btn-ghost:hover{ border-color: var(--ink); }
.btn-arrow{ transition: transform 0.15s ease; }
.btn:hover .btn-arrow{ transform: translateX(3px); }

/* ---------------------------------- layout -------------------------------- */

section{ padding: 96px 0; border-bottom: 1px solid var(--line); }
section:last-of-type{ border-bottom: none; }
.section-head{
  max-width: 620px;
  margin-bottom: 56px;
}
.section-head h2{ font-size: clamp(26px, 3.2vw, 36px); }
.section-head p{ margin-top: 14px; color: var(--mist); font-size: 17px; }

.dark{ background: var(--ink); color: var(--paper); border-bottom: none; }
.dark .eyebrow{ color: var(--steel-light); }
.dark .eyebrow::before{ background: var(--steel-light); }
.dark .section-head p{ color: #9AA5AE; }

/* ------------------------------- hero ------------------------------- */

.hero{
  padding: 88px 0 40px;
  border-bottom: none;
}
.hero-grid{
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 56px;
  align-items: center;
}
.hero h1{
  font-size: clamp(34px, 4.6vw, 54px);
  max-width: 15ch;
}
.hero .lede{
  margin-top: 22px;
  font-size: 18px;
  color: var(--ink-soft);
  max-width: 46ch;
}
.hero-actions{
  margin-top: 34px;
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}
.hero-figure{
  border: 1px solid var(--line);
  background: #FFFFFF;
  border-radius: 4px;
  padding: 20px 20px 16px;
}
.hero-figure-caption{
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--mist);
  display: flex;
  justify-content: space-between;
  margin-top: 10px;
  letter-spacing: 0.03em;
}

/* --------------------------- signal trace svg --------------------------- */

.trace-row{ display: flex; align-items: center; gap: 14px; }
.trace-row + .trace-row{ margin-top: 6px; }
.trace-label{
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--steel);
  width: 26px;
  flex: none;
}
.trace-row svg{ flex: 1; }
.trace-row path{
  fill: none;
  stroke: var(--steel-light);
  stroke-width: 1.5;
  stroke-linecap: round;
  stroke-dasharray: 620;
  stroke-dashoffset: 620;
  animation: draw 1.6s ease forwards;
}
.trace-row:nth-child(1) path{ animation-delay: 0.05s; stroke: #B7C1C8; }
.trace-row:nth-child(2) path{ animation-delay: 0.35s; stroke: var(--steel-light); }
.trace-row:nth-child(3) path{ animation-delay: 0.65s; stroke: var(--steel); }
.trace-row:nth-child(4) path{ animation-delay: 0.95s; stroke: var(--signal); stroke-width: 2; }
@keyframes draw{ to{ stroke-dashoffset: 0; } }
@media (prefers-reduced-motion: reduce){
  .trace-row path{ animation: none; stroke-dashoffset: 0; }
}

/* ------------------------------ chip / stat row ------------------------------ */

.chip-row{
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  margin-top: 40px;
}
.chip{
  background: var(--paper);
  padding: 22px 20px;
}
.chip .k{
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--signal);
  letter-spacing: 0.06em;
}
.chip .v{
  margin-top: 8px;
  font-size: 15px;
  color: var(--ink-soft);
}

/* ------------------------------- layer cards ------------------------------- */

.layer-list{ display: flex; flex-direction: column; border-top: 1px solid var(--line); }
.layer{
  display: grid;
  grid-template-columns: 90px 1fr 1.3fr;
  gap: 28px;
  padding: 30px 0;
  border-bottom: 1px solid var(--line);
  align-items: start;
}
.layer .tag{
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--signal);
  padding-top: 3px;
}
.layer h3{ font-size: 19px; }
.layer .desc{ color: var(--mist); font-size: 15px; }
.layer .examples{
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--steel);
  line-height: 1.9;
}

/* --------------------------------- cards grid --------------------------------- */

.card-grid{
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}
.card{
  background: var(--paper);
  padding: 30px 26px;
}
.card h3{ font-size: 17px; margin-bottom: 10px; }
.card p{ color: var(--mist); font-size: 14.5px; }
.card .tag{
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--steel);
  letter-spacing: 0.05em;
  margin-bottom: 14px;
  display: block;
}

/* ---------------------------------- cta band ---------------------------------- */

.cta-band{
  background: var(--ink);
  color: var(--paper);
  border-bottom: none;
  padding: 80px 0;
}
.cta-band .wrap{
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 40px;
  flex-wrap: wrap;
}
.cta-band h2{ font-size: clamp(24px, 3vw, 32px); max-width: 22ch; }
.cta-band p{ color: #9AA5AE; margin-top: 10px; }

/* ---------------------------------- footer ---------------------------------- */

footer{
  padding: 48px 0;
}
.footer-grid{
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  gap: 24px;
  flex-wrap: wrap;
}
.footer-links{
  display: flex;
  gap: 28px;
  list-style: none;
  padding: 0; margin: 0;
  font-size: 13.5px;
}
.footer-links a{ text-decoration: none; color: var(--mist); }
.footer-links a:hover{ color: var(--ink); }
.footer-meta{ font-family: var(--font-mono); font-size: 12px; color: var(--mist); }

/* ------------------------------- page hero (sub pages) ------------------------------- */

.page-hero{ padding: 72px 0 64px; }
.page-hero h1{ font-size: clamp(30px, 4vw, 44px); max-width: 20ch; }
.page-hero .lede{ margin-top: 18px; font-size: 17px; color: var(--ink-soft); max-width: 56ch; }

/* --------------------------------- pipeline (product page) --------------------------------- */

.pipeline{
  display: flex;
  align-items: center;
  gap: 0;
  flex-wrap: wrap;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--steel);
  margin: 8px 0 48px;
}
.pipeline .node{
  border: 1px solid var(--line-dark);
  padding: 8px 14px;
  border-radius: 3px;
  color: var(--ink);
  background: var(--paper);
}
.pipeline .arrow{ padding: 0 12px; color: var(--mist); }

/* --------------------------------- two-col --------------------------------- */

.two-col{
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 56px;
  align-items: start;
}

.quote-block{
  border-left: 2px solid var(--signal);
  padding-left: 22px;
  font-family: var(--font-display);
  font-size: 22px;
  line-height: 1.4;
  color: var(--ink);
  max-width: 60ch;
}

.list-plain{ list-style: none; margin: 0; padding: 0; }
.list-plain li{
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
  display: flex;
  gap: 14px;
  font-size: 15px;
  color: var(--ink-soft);
}
.list-plain li::before{
  content: "—";
  color: var(--signal);
  font-family: var(--font-mono);
  flex: none;
}

/* ------------------------------- contact form ------------------------------- */

.form-grid{
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
}
.form-grid .full{ grid-column: 1 / -1; }
label{
  display: block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--steel);
  margin-bottom: 8px;
}
input, textarea, select{
  width: 100%;
  font-family: var(--font-body);
  font-size: 15px;
  padding: 12px 14px;
  border: 1px solid var(--line-dark);
  border-radius: 3px;
  background: #fff;
  color: var(--ink);
}
input:focus, textarea:focus, select:focus{
  outline: 2px solid var(--signal);
  outline-offset: 1px;
  border-color: var(--signal);
}
textarea{ resize: vertical; min-height: 120px; }
.form-note{ font-size: 13px; color: var(--mist); margin-top: 18px; }

/* --------------------------------- responsive --------------------------------- */

@media (max-width: 900px){
  .hero-grid{ grid-template-columns: 1fr; }
  .two-col{ grid-template-columns: 1fr; gap: 36px; }
  .card-grid{ grid-template-columns: 1fr; }
  .chip-row{ grid-template-columns: 1fr 1fr; }
  .layer{ grid-template-columns: 1fr; gap: 10px; }
  .layer .tag{ padding-top: 0; }
  .form-grid{ grid-template-columns: 1fr; }
}

@media (max-width: 720px){
  .nav-links{
    position: fixed;
    inset: 72px 0 0 0;
    background: var(--paper);
    flex-direction: column;
    align-items: flex-start;
    padding: 28px var(--pad);
    gap: 22px;
    transform: translateY(-8px);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.15s ease, transform 0.15s ease;
    border-bottom: 1px solid var(--line);
  }
  .nav-links.open{ opacity: 1; transform: translateY(0); pointer-events: auto; }
  .nav-links a{ font-size: 16px; }
  .nav-cta .btn-primary{ display: none; }
  .nav-links .btn-primary{ display: inline-flex; margin-top: 6px; }
  .nav-toggle{
    display: block;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
  }
  .nav-toggle span{
    display: block;
    width: 20px; height: 1.5px;
    background: var(--ink);
    margin: 4px 0;
  }
  .cta-band .wrap{ flex-direction: column; align-items: flex-start; }
  .footer-grid{ flex-direction: column; align-items: flex-start; }
}