/* BISS v2 — extensive graphics, minimal language. No images, no frameworks. */

:root {
  /* Dark is the default theme. */
  --paper: #101110;
  --ink: #dddbd2;
  --faint: #84837a;
  --hair: #dddbd224;
  --accent: #3ddc84;
  --mono: ui-monospace, "SF Mono", "Cascadia Code", Menlo, Consolas, monospace;
  --sans: "Helvetica Neue", Helvetica, Arial, system-ui, sans-serif;
  --railw: 4.5rem;
}
/* Opt-in light theme — toggled via the nav and remembered in localStorage. */
:root[data-theme="light"] {
  --paper: #f4f3ee;
  --ink: #16161a;
  --faint: #76756d;
  --hair: #16161a1f;
  --accent: #0a6e3c;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.mono { font-family: var(--mono); }
a { color: inherit; text-decoration: none; }
canvas { display: block; width: 100%; }

/* ── Left rail: vertical oscilloscope, your scroll is the signal ── */
.rail {
  position: fixed;
  left: 0; top: 0; bottom: 0;
  width: var(--railw);
  border-right: 1px solid var(--hair);
  z-index: 50;
  pointer-events: none;
}
.rail canvas { width: 100%; height: 100%; }
.rail-stat {
  position: absolute;
  bottom: 0.7rem;
  left: 50%;
  transform: translateX(-50%);
  font-size: 0.55rem;
  color: var(--faint);
  white-space: nowrap;
}

/* ── Nav ─────────────────────────────────────────────────── */
/* Soft scrim beneath the fixed nav: fades passing section labels out
   before they collide with the nav text. Sits below the nav (z 39 < 40)
   and outside its blend, so the difference blending is unaffected. */
body::before {
  content: "";
  position: fixed;
  top: 0; left: 0; right: 0;
  height: 3.4rem;
  background: linear-gradient(var(--paper) 30%, transparent);
  z-index: 39;
  pointer-events: none;
}
.nav {
  position: fixed;
  top: 0; left: var(--railw); right: 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.9rem 2rem;
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  z-index: 40;
  mix-blend-mode: difference;
  color: #aaa;
}
.nav nav a { margin-left: 1.6rem; opacity: 0.75; }
.nav nav a:hover { opacity: 1; }
.wordmark { font-weight: 700; letter-spacing: 0.3em; }

/* theme toggle — a half-lit disc, no image file, drawn in CSS */
.theme-toggle {
  -webkit-appearance: none;
  appearance: none;
  margin-left: 1.6rem;
  width: 0.95rem;
  height: 0.95rem;
  padding: 0;
  border: 1px solid currentColor;
  border-radius: 50%;
  background: linear-gradient(90deg, currentColor 0 50%, transparent 50% 100%);
  color: inherit;
  cursor: pointer;
  vertical-align: middle;
  transition: transform 0.35s ease, opacity 0.15s;
  opacity: 0.75;
}
.theme-toggle:hover { opacity: 1; transform: rotate(180deg); }
.theme-toggle:focus-visible { outline: 1px solid currentColor; outline-offset: 3px; }

/* ── Hero ────────────────────────────────────────────────── */
.hero {
  position: relative;
  height: 100svh;
  min-height: 540px;
  overflow: hidden;
}
#flow {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}
.hero-text {
  position: relative;
  z-index: 2;
  max-width: 620px;
  padding: 0 2rem;
  margin-left: clamp(3rem, 12vw, 11rem);
  top: 50%;
  transform: translateY(-50%);
  pointer-events: none;
}
.kicker {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.25em;
  color: var(--faint);
  margin: 0 0 1rem;
}
h1 {
  font-size: clamp(3rem, 9vw, 6.5rem);
  line-height: 0.98;
  font-weight: 250;
  letter-spacing: -0.02em;
  margin: 0 0 1.4rem;
}
.lede { max-width: 46ch; color: var(--ink); margin: 0 0 1.2rem; }
.hero-tags { margin: 1.4rem 0 0; max-width: 46ch; line-height: 1.8; }

/* ── Sections ────────────────────────────────────────────── */
.block {
  padding: 7rem 2rem 4rem;
  margin-left: var(--railw);
  max-width: 1180px;
}
h2 {
  font-size: clamp(1.6rem, 3.5vw, 2.4rem);
  font-weight: 300;
  margin: 0 0 3rem;
  letter-spacing: -0.01em;
}
.idx { font-size: 0.6em; color: var(--accent); vertical-align: 0.25em; margin-right: 0.6rem; }

/* capabilities */
.cap-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2.5rem;
}
.cap { margin: 0; border-top: 1px solid var(--ink); }
.cap canvas { border-bottom: 1px solid var(--hair); }
.cap h3 { font-size: 1rem; font-weight: 600; margin: 1rem 0 0.4rem; }
.cap p { font-size: 0.86rem; color: var(--ink); margin: 0.4rem 0; }
.tags { font-size: 0.62rem; color: var(--faint); letter-spacing: 0.06em; text-transform: uppercase; }

/* work rows */
.row {
  display: grid;
  grid-template-columns: 220px 1fr auto;
  gap: 2.5rem;
  align-items: center;
  padding: 2.2rem 0;
  border-top: 1px solid var(--hair);
}
.row:last-child { border-bottom: 1px solid var(--hair); }
.row-art { width: 220px; height: 120px; }
.row-text h3 { margin: 0 0 0.4rem; font-size: 1.05rem; font-weight: 600; }
.row-text p { margin: 0; font-size: 0.88rem; max-width: 62ch; }
.row-src {
  margin: 0.7rem 0 0; font-size: 0.66rem; letter-spacing: 0.05em;
  color: var(--faint);
}
.row-src a { color: var(--ink); }
.row-text p + p { margin-top: 0.7rem; }
.row-id { font-size: 0.62rem; color: var(--faint); letter-spacing: 0.15em; }

/* company */
.col-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2.5rem 4rem;
  max-width: 980px;
}
.col-h {
  font-size: 0.62rem;
  text-transform: uppercase;
  letter-spacing: 0.2em;
  color: var(--accent);
  margin: 0 0 0.6rem;
  border-top: 1px solid var(--ink);
  padding-top: 0.6rem;
}
.col-grid p { font-size: 0.88rem; margin: 0; }

/* contact */
.contact-lede { max-width: 52ch; margin: 0 0 2.5rem; }
.contact-grid { max-width: 560px; }
.c-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 2rem;
  padding: 0.55rem 0;
  border-top: 1px solid var(--hair);
  font-size: 0.78rem;
}
.c-row:last-child { border-bottom: 1px solid var(--hair); }
.c-k {
  text-transform: uppercase;
  letter-spacing: 0.2em;
  font-size: 0.6rem;
  color: var(--faint);
}
.c-v { color: var(--ink); letter-spacing: 0.04em; }
a.c-v { transition: color 0.15s; }
a.c-v:hover { color: var(--accent); }

/* footer */
.foot {
  margin-left: var(--railw);
  padding: 3rem 0 1.4rem;
}
#pulse { height: 48px; margin-bottom: 0.8rem; }
.foot p {
  font-size: 0.62rem;
  color: var(--faint);
  letter-spacing: 0.06em;
  text-align: center;
}

/* ── 02 Method ───────────────────────────────────────────── */
.method-lede { max-width: 64ch; margin: 0 0 2.6rem; }
.method-fig { position: relative; margin: 0 0 3rem; border-top: 1px solid var(--ink); }
.method-fig canvas {
  width: 100%;
  height: clamp(280px, 33vw, 410px);
  border-bottom: 1px solid var(--hair);
}
.method-cap {
  display: block;
  font-size: 0.6rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--faint);
  padding-top: 0.7rem;
}
.method-tip {
  position: absolute;
  z-index: 6;
  width: max-content;
  max-width: 260px;
  pointer-events: none;
  background: var(--paper);
  border: 1px solid var(--accent);
  padding: 0.6rem 0.7rem 0.62rem;
  box-shadow: 0 8px 24px -14px rgba(0, 0, 0, 0.5);
  opacity: 0;
  transform: translate(-50%, calc(-100% - 4px));
  transition: opacity 0.16s ease, transform 0.16s ease;
}
.method-tip.on { opacity: 1; transform: translate(-50%, calc(-100% - 12px)); }
/* vertical rail (phones / narrow): tooltip sits beside the node, not above it */
.method-tip.side { transform: translate(8px, -50%); }
.method-tip.side.on { transform: translate(16px, -50%); }
.method-tip .tip-t {
  display: block;
  font-size: 0.6rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.35rem;
}
.method-tip .tip-d {
  display: block;
  font-family: var(--sans);
  font-size: 0.76rem;
  line-height: 1.5;
  color: var(--ink);
}
.method-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2.2rem 2.6rem;
}
.method-steps li { margin: 0; display: flex; flex-direction: column; }
.ms-i {
  display: block;
  font-size: 0.6rem;
  letter-spacing: 0.2em;
  color: var(--accent);
  border-top: 1px solid var(--ink);
  padding-top: 0.55rem;
}
.method-steps h3 { font-size: 0.98rem; font-weight: 600; margin: 0.5rem 0 0.35rem; }
.method-steps p { font-size: 0.82rem; color: var(--ink); margin: 0 0 1.1rem; max-width: 40ch; }
.ms-fig { margin-top: auto; width: 100%; height: 66px; border-top: 1px solid var(--hair); }

/* ── 04 Field partners ───────────────────────────────────── */
.partners-lede { max-width: 62ch; margin: 0 0 2.6rem; }

.rig-fig { position: relative; margin: 0 0 3.2rem; border-top: 1px solid var(--ink); }
.rig-fig canvas {
  width: 100%;
  height: clamp(260px, 28vw, 380px);
  border-bottom: 1px solid var(--hair);
}
.rig-cap {
  display: block;
  font-size: 0.6rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--faint);
  padding-top: 0.7rem;
}
/* companion figures: plan view full-width, corner + terminal side by side */
.rig-fig canvas[data-sketch="plan"] { height: clamp(220px, 24vw, 330px); }
.rig-duo {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0 2.5rem;
}
.rig-duo .rig-fig canvas { height: clamp(180px, 18vw, 250px); }

.partner {
  display: grid;
  grid-template-columns: 92px 1fr auto;
  gap: 2.2rem;
  align-items: center;
  padding: 2.4rem 0;
  border-top: 1px solid var(--hair);
}
.partner:last-child { border-bottom: 1px solid var(--hair); }
/* monogram tile — a hairline square with two accent corner brackets, no image */
.partner-mark {
  position: relative;
  width: 92px;
  height: 92px;
  display: grid;
  place-items: center;
  border: 1px solid var(--ink);
  font-size: 1.65rem;
  font-weight: 600;
  letter-spacing: 0.16em;
  color: var(--ink);
}
.partner-mark::before,
.partner-mark::after {
  content: "";
  position: absolute;
  width: 11px;
  height: 11px;
  border: 0 solid var(--accent);
}
.partner-mark::before { top: -1px; left: -1px; border-top-width: 2px; border-left-width: 2px; }
.partner-mark::after { bottom: -1px; right: -1px; border-bottom-width: 2px; border-right-width: 2px; }

.partner-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 0.4rem 1.4rem;
  flex-wrap: wrap;
  margin-bottom: 0.55rem;
}
.partner-head h3 { margin: 0; font-size: 1.1rem; font-weight: 600; }
.partner-loc {
  font-size: 0.6rem;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  color: var(--faint);
  white-space: nowrap;
}
.partner-body p { margin: 0 0 0.7rem; font-size: 0.88rem; max-width: 66ch; }
.partner-body p.partner-tags {
  font-size: 0.62rem;
  color: var(--faint);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  max-width: none;
  margin-bottom: 0.9rem;
}
.partner-link {
  display: inline-block;
  font-size: 0.68rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  opacity: 0.85;
  transition: opacity 0.15s;
}
.partner-link:hover { opacity: 1; }
.partner-id { font-size: 0.62rem; color: var(--faint); letter-spacing: 0.15em; align-self: start; }

/* ── Small screens ───────────────────────────────────────── */
@media (max-width: 880px) {
  .rail { display: none; }
  .nav { left: 0; }
  .block, .foot { margin-left: 0; }
  .hero-text { margin-left: 0; }
  .hero-foot { left: 2rem; }
  .cap-grid, .col-grid, .method-steps, .rig-duo { grid-template-columns: 1fr; }
  .rig-duo .rig-fig canvas { height: clamp(180px, 34vw, 280px); }
  .row { grid-template-columns: 1fr; gap: 1rem; }
  .row-art { width: 100%; }
  .row-id { display: none; }
  .partner { grid-template-columns: 1fr; gap: 1.2rem; }
  .partner-id { display: none; }
}

/* Phones / small tablets: compact numbered nav so five links never overflow. */
@media (max-width: 700px) {
  .nav { padding: 0.75rem 1rem; }
  .nav nav a { margin-left: 0; padding: 0.55rem 0.5rem; font-size: 0.82rem; }
  /* keep the full label for screen readers; show only the index visually */
  .nav nav a .lk-t {
    position: absolute; width: 1px; height: 1px;
    margin: -1px; padding: 0; border: 0;
    overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap;
  }
  .theme-toggle { margin-left: 0.4rem; }
}

/* Phones: the method rail flips to vertical (art.js) — give it room to breathe. */
@media (max-width: 620px) {
  .method-fig canvas { height: clamp(460px, 122vw, 600px); }
  .rig-fig canvas { height: clamp(150px, 46vw, 240px); }
  .rig-fig canvas[data-sketch="plan"],
  .rig-duo .rig-fig canvas { height: clamp(140px, 42vw, 220px); }
}

@media (max-width: 480px) {
  .method-tip { max-width: min(240px, 80vw); }
  .c-row { flex-wrap: wrap; gap: 0.2rem 1rem; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .theme-toggle { transition: none; }
  .theme-toggle:hover { transform: none; }
}

/* ── 07 FAQ ─────────────────────────────────────────────── */
.faq { max-width: 72ch; }
.faq details { border-bottom: 1px solid var(--hair); }
.faq details:first-of-type { border-top: 1px solid var(--ink); }
.faq summary {
  cursor: pointer;
  padding: 1.1rem 0;
  list-style: none;
  font-weight: 500;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::before { content: "+"; color: var(--accent); margin-right: 0.9rem; }
.faq details[open] summary::before { content: "−"; }
.faq details p {
  font-size: 0.9rem;
  color: var(--ink);
  margin: 0 0 1.2rem;
  padding-left: 1.6rem;
  max-width: 62ch;
}

/* ---- skip link ---- */
.skip { position: fixed; top: -3rem; left: 1rem; z-index: 100;
  padding: 0.5rem 0.9rem; background: var(--ink); color: var(--paper);
  font-size: 0.62rem; letter-spacing: 0.14em; text-transform: uppercase;
  text-decoration: none; transition: top 0.15s; }
.skip:focus-visible { top: 0.6rem; }

/* ---- h1 accent word ---- */
.h1-accent { color: var(--accent); }