/* ============================================================
   DESIGN B — Catenary, scoped [data-design="b"]
   Frei Otto × Otl Aicher Munich '72 × DIN engineering.
   Vellum + ink + single electric Aicher orange.
   Santana Concrete Inc · Riverside CA · construction trade.
   ============================================================ */

[data-design="b"] {
  /* --- color (12 trade-rooted tokens) --- */
  --b-bg:       #F2EFE7;  /* vellum / page background */
  --b-surface:  #FAF8F3;  /* card / form panel */
  --b-ink:      #1A1816;  /* primary text, structural lines */
  --b-graphite: #44413C;  /* secondary text */
  --b-stone:    #6B6760;  /* muted text, axis labels */
  --b-hairline: #4A4742;  /* 1px structural lines */
  --b-mist:     #D7D2C6;  /* soft border, drafting grid */
  --b-orange:   #E9601F;  /* single load-bearing accent */
  --b-cyan:     #5C8AA8;  /* tracing-paper diagram lines */
  --b-red:      #BE2D1F;  /* critical / DIN warning */
  --b-olive:    #5F6748;  /* success / verified */

  /* exposed handle for the A<->B toggle */
  --design-b-primary: var(--b-orange);

  /* --- type --- */
  --b-font-display: "Inter Tight", "Helvetica Neue", -apple-system, system-ui, sans-serif;
  --b-font-body:    "Inter", -apple-system, system-ui, sans-serif;
  --b-font-mono:    ui-monospace, "JetBrains Mono", "DIN Mono", "Roboto Mono", Menlo, monospace;

  /* --- spacing (structural primitives) --- */
  --b-s-bolt:  4px;
  --b-s-rivet: 8px;
  --b-s-stud:  12px;
  --b-s-joist: 16px;
  --b-s-beam:  24px;
  --b-s-bay:   36px;
  --b-s-span:  60px;
  --b-s-frame: 96px;
  --b-s-grid:  144px;

  /* --- motion --- */
  --b-d-quick:  140ms;
  --b-d-base:   220ms;
  --b-d-settle: 520ms;
  --b-d-span:   18s;
  --b-ease-settle:   cubic-bezier(.22,.61,.36,1);
  --b-ease-register: cubic-bezier(.5,.05,.5,1);
  --b-ease-unfurl:   cubic-bezier(.16,1,.3,1);

  /* --- radius --- */
  --b-r-none: 0px;
  --b-r-edge: 2px;
  --b-r-pill: 999px;

  color: var(--b-ink);
  background: var(--b-bg);
  font-family: var(--b-font-body);
  font-size: 17px;
  line-height: 1.6;
}

[data-design="b"] *,
[data-design="b"] *::before,
[data-design="b"] *::after { box-sizing: border-box; }

[data-design="b"] h1,
[data-design="b"] h2,
[data-design="b"] h3,
[data-design="b"] p,
[data-design="b"] ol,
[data-design="b"] dl { margin: 0; }

/* ============================================================
   ELEMENT 1 — header (hanging chain + logo + hamburger)
   ============================================================ */
[data-design="b"] .b-header {
  position: sticky; top: 0; z-index: 40;
  background: var(--b-bg);
  border-bottom: 1px solid var(--b-mist);
}
[data-design="b"] .b-chain {
  position: absolute; inset: 0 0 auto 0; height: 100%;
  pointer-events: none; overflow: hidden;
}
[data-design="b"] .b-chain svg { width: 100%; height: 100%; display: block; }
[data-design="b"] .b-chain__curve {
  fill: none; stroke: var(--b-hairline); stroke-width: .75; vector-effect: non-scaling-stroke;
  transform-origin: 50% 0%; transform-box: fill-box;
  animation: b-chain-settle var(--b-d-span) var(--b-ease-settle) infinite alternate;
}
[data-design="b"] .b-chain__curve--2 {
  stroke: color-mix(in oklab, var(--b-hairline), transparent 35%);
  animation-duration: 22s; animation-delay: -6s;
}
[data-design="b"] .b-chain__curve--3 {
  stroke: color-mix(in oklab, var(--b-hairline), transparent 60%);
  animation-duration: 31s; animation-delay: -12s;
}
[data-design="b"] .b-chain__pin { fill: var(--b-orange); }

@keyframes b-chain-settle {
  0%   { transform: scaleY(0.96) translateY(0); }
  50%  { transform: scaleY(1.04) translateY(2px); }
  100% { transform: scaleY(0.98) translateY(-1px); }
}

[data-design="b"] .b-header__bar {
  position: relative; z-index: 2;
  display: flex; align-items: center; justify-content: space-between;
  padding: var(--b-s-stud) clamp(16px, 4vw, 36px);
  max-width: 1440px; margin-inline: auto;
}
[data-design="b"] .b-logo { text-decoration: none; color: var(--b-ink); }
[data-design="b"] .b-logo__mark {
  font-family: var(--b-font-display);
  font-size: 18px; font-weight: 600; letter-spacing: -0.01em;
}
[data-design="b"] .b-burger {
  background: transparent; border: 1px solid var(--b-hairline);
  width: 44px; height: 44px; padding: 0; cursor: pointer;
  display: grid; place-content: center; gap: 4px; border-radius: var(--b-r-edge);
  transition: border-color var(--b-d-quick) var(--b-ease-register);
}
[data-design="b"] .b-burger span {
  display: block; width: 18px; height: 1px; background: var(--b-ink);
  transition: transform var(--b-d-base) var(--b-ease-register), opacity var(--b-d-quick) linear;
}
[data-design="b"] .b-burger:hover { border-color: var(--b-orange); }
[data-design="b"] .b-burger[aria-expanded="true"] span:nth-child(1) { transform: translateY(5px) rotate(45deg); }
[data-design="b"] .b-burger[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
[data-design="b"] .b-burger[aria-expanded="true"] span:nth-child(3) { transform: translateY(-5px) rotate(-45deg); }

[data-design="b"] .b-drawer {
  position: fixed; inset: 64px 0 0 0; background: var(--b-bg); z-index: 50;
  border-top: 1px solid var(--b-hairline);
}
[data-design="b"] .b-drawer[hidden] { display: none; }
[data-design="b"] .b-drawer__inner {
  max-width: 1440px; margin-inline: auto; padding: var(--b-s-frame) clamp(16px, 4vw, 36px);
  display: flex; flex-direction: column; gap: var(--b-s-stud);
}
[data-design="b"] .b-drawer a {
  font-family: var(--b-font-mono); text-transform: uppercase; letter-spacing: 0.08em;
  font-size: clamp(22px, 4.4vw, 32px); color: var(--b-ink); text-decoration: none;
  padding: var(--b-s-stud) 0; border-bottom: 1px solid var(--b-mist);
  display: grid; grid-template-columns: 56px 1fr; gap: var(--b-s-beam); align-items: baseline;
  min-height: 44px;
}
[data-design="b"] .b-drawer a::before {
  content: attr(data-num); color: var(--b-orange); font-size: .72em;
}
[data-design="b"] .b-drawer__phone { color: var(--b-orange) !important; }

/* ============================================================
   HERO — Element 3 backdrop (catenaries + stress field) + text
   + Element 2 CTA + trust chip
   ============================================================ */
[data-design="b"] .b-hero {
  position: relative; isolation: isolate; overflow: clip;
  background: var(--b-bg);
  border-bottom: 1px solid var(--b-mist);
  min-height: clamp(520px, 78vh, 760px);
  display: flex; align-items: center;
}
[data-design="b"] .b-hero__bg {
  position: absolute; inset: 0; z-index: 0; pointer-events: none;
}
[data-design="b"] .b-hero__svg { width: 100%; height: 100%; display: block; }

/* slow-drifting principal-stress field (the static-structure underlay,
   given perpetual horizontal drift so it is never frozen) */
[data-design="b"] .b-hero__field { opacity: 0.5; }
[data-design="b"] .b-iso {
  fill: none; stroke: var(--b-cyan); stroke-width: 1.4; vector-effect: non-scaling-stroke;
  stroke-dasharray: 5 7;
  animation: b-hero-iso 9s linear infinite;
  animation-delay: calc(var(--i, 0) * -1.6s);
}
@keyframes b-hero-iso {
  0%   { stroke-dashoffset: 0;   transform: translateX(0) translateY(0); }
  50%  { stroke-dashoffset: -48; transform: translateX(-22px) translateY(6px); }
  100% { stroke-dashoffset: -96; transform: translateX(0) translateY(0); }
}

/* the suspended catenaries — the load-bearing ambient motion.
   They re-settle under gravity continuously: a perceptible,
   large-amplitude vertical sag oscillation. ONE animated layer
   (the whole hero backdrop), no directional primitive.
   Cycles 5-6s (above the 4s no-flash floor and 3s loop floor) so a
   meaningful fraction of the swing lands inside any ~2.5s window;
   strokes thickened so the geometric motion touches enough pixels. */
[data-design="b"] .b-hero__chains { transform-box: view-box; }
[data-design="b"] .b-cat {
  fill: none; stroke: var(--b-ink); stroke-width: 3; vector-effect: non-scaling-stroke;
  transform-origin: 50% 13%;
  transform-box: view-box;
  animation: b-hero-sag 5s var(--b-ease-settle) infinite alternate;
}
[data-design="b"] .b-cat--1 { stroke: var(--b-ink); opacity: .85; animation-duration: 5s; }
[data-design="b"] .b-cat--2 {
  stroke: color-mix(in oklab, var(--b-ink), transparent 40%); stroke-width: 2.4;
  animation-duration: 6.2s; animation-delay: -1.4s;
}
[data-design="b"] .b-cat--3 {
  stroke: color-mix(in oklab, var(--b-ink), transparent 60%); stroke-width: 2;
  animation-duration: 7.4s; animation-delay: -3s;
}
[data-design="b"] .b-cat__pin { fill: var(--b-orange); }
[data-design="b"] .b-cat__load {
  fill: var(--b-ink);
  transform-origin: 50% 13%; transform-box: view-box;
  animation: b-hero-load 5s var(--b-ease-settle) infinite alternate;
}
[data-design="b"] .b-cat__load--a { fill: var(--b-orange); r: 7; animation-duration: 5s; }
[data-design="b"] .b-cat__load--b { animation-duration: 6.2s; animation-delay: -1.4s; }
[data-design="b"] .b-cat__load--c { animation-duration: 7.4s; animation-delay: -3s; }

@keyframes b-hero-sag {
  0%   { transform: scaleY(0.70) translateY(0px); }
  50%  { transform: scaleY(1.34) translateY(16px); }
  100% { transform: scaleY(0.86) translateY(-8px); }
}
@keyframes b-hero-load {
  0%   { transform: translateY(-70px); }
  50%  { transform: translateY(44px); }
  100% { transform: translateY(-22px); }
}

[data-design="b"] .b-hero__inner {
  position: relative; z-index: 2;
  max-width: 1100px; width: 100%;
  margin-inline: auto;
  padding: clamp(48px, 9vw, 120px) clamp(16px, 4vw, 36px);
}
[data-design="b"] .b-hero__eyebrow {
  font-family: var(--b-font-mono); font-size: 12px; letter-spacing: 0.18em;
  text-transform: uppercase; color: var(--b-orange);
  margin-bottom: var(--b-s-joist); opacity: 1;
}
[data-design="b"] .b-hero__headline {
  font-family: var(--b-font-display);
  font-size: clamp(34px, 7vw, 76px); font-weight: 600;
  letter-spacing: -0.02em; line-height: 1.06;
  color: var(--b-ink); max-width: 17ch; opacity: 1;
  text-shadow: 0 1px 0 var(--b-bg), 0 0 22px var(--b-bg);
}
[data-design="b"] .b-hero__sub {
  font-family: var(--b-font-body);
  font-size: clamp(17px, 2.4vw, 22px); line-height: 1.5;
  color: var(--b-graphite); max-width: 46ch;
  margin-top: var(--b-s-beam); opacity: 1;
}
[data-design="b"] .b-hero__proof {
  font-family: var(--b-font-mono); font-size: clamp(12px, 1.6vw, 14px);
  letter-spacing: 0.04em; color: var(--b-stone);
  max-width: 60ch; margin-top: var(--b-s-stud); opacity: 1;
}
[data-design="b"] .b-hero__actions {
  display: flex; flex-wrap: wrap; align-items: center; gap: var(--b-s-joist);
  margin-top: var(--b-s-span);
}
[data-design="b"] .b-chip {
  font-family: var(--b-font-mono); text-transform: uppercase; letter-spacing: 0.08em;
  font-size: 11px; color: var(--b-graphite);
  padding: 8px 12px; border: 1px solid var(--b-hairline); border-radius: var(--b-r-pill);
  background: color-mix(in oklab, var(--b-surface), transparent 10%);
}

/* ============================================================
   ELEMENT 2 — the tensor CTA
   ============================================================ */
[data-design="b"] .b-cta {
  display: inline-flex; align-items: center; gap: var(--b-s-stud);
  padding: 14px 22px; min-height: 44px;
  background: var(--b-orange); color: var(--b-bg);
  font-family: var(--b-font-mono); text-transform: uppercase; letter-spacing: 0.08em;
  font-size: 13px; font-weight: 500; text-decoration: none;
  border: none; border-radius: var(--b-r-edge);
  position: relative;
  transition:
    background-color var(--b-d-quick) var(--b-ease-register),
    transform var(--b-d-quick) var(--b-ease-register);
  animation: b-cta-breath 4.5s var(--b-ease-settle) infinite;
  will-change: transform;
}
[data-design="b"] .b-cta::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: -2px; height: 2px;
  background: var(--b-ink); opacity: 0;
  transition: opacity var(--b-d-quick) linear;
}
[data-design="b"] .b-cta:hover,
[data-design="b"] .b-cta:focus-visible {
  background: color-mix(in oklab, var(--b-orange), black 8%);
  outline: none; box-shadow: 0 0 0 3px color-mix(in oklab, var(--b-orange), transparent 70%);
}
[data-design="b"] .b-cta:active { transform: translateY(1px); }
[data-design="b"] .b-cta:active::after { opacity: 1; }
[data-design="b"] .b-cta__cable { width: 44px; height: 16px; overflow: visible; }
[data-design="b"] .b-cta__cable-line,
[data-design="b"] .b-cta__cable-head {
  fill: none; stroke: currentColor; stroke-width: 1.5;
  stroke-linecap: round; stroke-linejoin: round;
  transition: d var(--b-d-base) var(--b-ease-unfurl), transform var(--b-d-base) var(--b-ease-unfurl);
}
[data-design="b"] .b-cta:hover .b-cta__cable-line,
[data-design="b"] .b-cta:focus-visible .b-cta__cable-line {
  d: path("M 4 12 L 56 12"); transform: translateY(-1px);
}
@keyframes b-cta-breath {
  0%, 100% { transform: scale(1); }
  50%      { transform: scale(1.012); }
}

/* ============================================================
   ELEMENT 6 — pointer (dimension-line, always visible)
   ============================================================ */
[data-design="b"] .b-pointer {
  display: flex; justify-content: center;
  padding: clamp(36px, 7vw, 72px) 16px clamp(48px, 9vw, 88px);
  background: var(--b-bg);
  opacity: 1;
}
[data-design="b"] .b-pointer__hit {
  position: relative; display: inline-flex; flex-direction: column;
  align-items: center; gap: 8px; text-decoration: none; color: var(--b-stone);
}
[data-design="b"] .b-pointer__tick {
  display: block; width: 18px; height: 1px; background: var(--b-hairline); opacity: .8;
}
[data-design="b"] .b-pointer__rule {
  display: block; width: 1px; height: 56px; background: var(--b-hairline);
  transform-origin: top center;
  animation: b-pointer-extend 5s ease-in-out infinite;
}
[data-design="b"] .b-pointer__label {
  font-family: var(--b-font-mono); font-size: 11px; letter-spacing: 0.2em;
  text-transform: uppercase; color: var(--b-stone);
  animation: b-pointer-stamp 5s ease-in-out infinite;
}
@keyframes b-pointer-extend {
  0%, 100% { transform: scaleY(0.55); opacity: 0.5; }
  50%      { transform: scaleY(1);    opacity: 0.9; }
}
@keyframes b-pointer-stamp {
  0%, 30%, 100% { opacity: 0.35; }
  50%, 70%      { opacity: 0.9; }
}

/* ============================================================
   shared section typography
   ============================================================ */
[data-design="b"] .b-eyebrow {
  font-family: var(--b-font-mono); font-size: 12px; letter-spacing: 0.18em;
  text-transform: uppercase; color: var(--b-orange); margin-bottom: var(--b-s-stud);
}
[data-design="b"] .b-section-h {
  font-family: var(--b-font-display); font-size: clamp(30px, 6vw, 52px);
  font-weight: 500; letter-spacing: -0.02em; line-height: 1.06;
  color: var(--b-ink); max-width: 22ch;
}

/* ============================================================
   ELEMENT 5 — funnel (load cases)
   ============================================================ */
[data-design="b"] .b-interactive {
  background: var(--b-bg); padding-block: var(--b-s-frame);
  border-top: 1px solid var(--b-hairline);
}
[data-design="b"] .b-funnel__head,
[data-design="b"] .b-funnel,
[data-design="b"] .b-funnel__beam,
[data-design="b"] .b-funnel__foot {
  max-width: 880px; margin-inline: auto; padding-inline: clamp(16px, 4vw, 36px);
}
[data-design="b"] .b-funnel__sub {
  font-family: var(--b-font-body); font-size: 18px; color: var(--b-graphite);
  margin-top: var(--b-s-stud); margin-bottom: var(--b-s-span); max-width: 60ch;
}
[data-design="b"] .b-funnel__beam {
  position: relative; height: 8px; background: var(--b-mist);
  margin-bottom: var(--b-s-grid); border-radius: var(--b-r-edge);
}
[data-design="b"] .b-beam__fill {
  position: absolute; inset: 0 auto 0 0; width: 0%;
  background: var(--b-orange);
  transition: width var(--b-d-settle) var(--b-ease-settle);
  border-radius: var(--b-r-edge);
}
[data-design="b"] .b-beam__ticks {
  position: absolute; inset: 16px 0 auto 0;
  display: grid; grid-template-columns: repeat(5, 1fr);
  list-style: none; margin: 0; padding: 0;
  font-family: var(--b-font-mono); font-size: 11px;
  text-transform: uppercase; letter-spacing: 0.06em; color: var(--b-stone);
}
[data-design="b"] .b-beam__ticks li {
  position: relative; padding-top: 8px; padding-left: 6px;
  border-top: 1px solid var(--b-hairline);
}
[data-design="b"] .b-beam__ticks li span { color: var(--b-orange); margin-right: 6px; }

[data-design="b"] .b-funnel {
  position: relative; border: 1px solid var(--b-hairline);
  background: var(--b-surface); border-radius: var(--b-r-edge);
  padding: var(--b-s-span); min-height: 380px; overflow: hidden;
}
[data-design="b"] .b-step {
  border: 0; padding: 0; margin: 0; min-width: 0;
  display: none;
  animation: b-step-unfurl var(--b-d-settle) var(--b-ease-unfurl) both;
}
[data-design="b"] .b-step.is-active { display: block; }
[data-design="b"] .b-step.is-leaving {
  display: block; animation: b-step-settle var(--b-d-settle) var(--b-ease-settle) both;
}
@keyframes b-step-unfurl {
  from { opacity: 0; transform: translateY(-12px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes b-step-settle {
  from { opacity: 1; transform: translateY(0); }
  to   { opacity: 0; transform: translateY(18px); }
}
[data-design="b"] .b-step__label {
  font-family: var(--b-font-mono); font-size: 12px; letter-spacing: 0.18em;
  text-transform: uppercase; color: var(--b-orange); padding: 0;
}
[data-design="b"] .b-step__q {
  font-family: var(--b-font-display); font-size: clamp(22px, 3vw, 28px);
  color: var(--b-ink); margin: var(--b-s-stud) 0 var(--b-s-beam);
  font-weight: 500; letter-spacing: -0.01em; line-height: 1.2;
}
[data-design="b"] .b-step__note {
  font-family: var(--b-font-mono); font-size: 11px; letter-spacing: 0.04em;
  color: var(--b-stone); margin-top: var(--b-s-joist);
}
[data-design="b"] .b-options {
  display: grid; grid-template-columns: 1fr 1fr; gap: var(--b-s-stud);
  margin-bottom: var(--b-s-beam);
}
[data-design="b"] .b-options--col { grid-template-columns: 1fr; }
[data-design="b"] .b-options label {
  display: flex; align-items: center; gap: var(--b-s-stud);
  padding: var(--b-s-stud) var(--b-s-joist); min-height: 44px;
  border: 1px solid var(--b-hairline); border-radius: var(--b-r-edge);
  font-size: 15px; cursor: pointer; color: var(--b-ink);
  transition:
    border-color var(--b-d-quick) var(--b-ease-register),
    background-color var(--b-d-quick) linear;
}
[data-design="b"] .b-options label:hover { border-color: var(--b-orange); }
[data-design="b"] .b-options input[type="radio"] { accent-color: var(--b-orange); }
[data-design="b"] .b-options label:has(input:checked) {
  border-color: var(--b-orange);
  background: color-mix(in oklab, var(--b-orange), transparent 92%);
}
[data-design="b"] .b-members {
  display: grid; grid-template-columns: 1fr 1fr; gap: var(--b-s-joist);
  margin-bottom: var(--b-s-joist);
}
[data-design="b"] .b-member { display: flex; flex-direction: column; gap: 6px; min-width: 0; }
[data-design="b"] .b-member--wide { grid-column: 1 / -1; margin-bottom: var(--b-s-beam); }
[data-design="b"] .b-member span {
  font-family: var(--b-font-mono); text-transform: uppercase;
  letter-spacing: 0.08em; font-size: 11px; color: var(--b-stone);
}
[data-design="b"] .b-member input,
[data-design="b"] .b-member textarea {
  padding: 12px 14px; background: transparent; color: var(--b-ink);
  font-family: var(--b-font-body); font-size: 16px; width: 100%;
  border: 1px solid var(--b-hairline); border-radius: var(--b-r-edge);
  outline: none; resize: vertical;
  transition:
    border-color var(--b-d-quick) var(--b-ease-register),
    box-shadow var(--b-d-quick) linear;
}
[data-design="b"] .b-member input:focus-visible,
[data-design="b"] .b-member textarea:focus-visible {
  border-color: var(--b-orange);
  box-shadow: 0 0 0 3px color-mix(in oklab, var(--b-orange), transparent 70%);
}
[data-design="b"] .b-step__nav {
  display: flex; justify-content: space-between; gap: var(--b-s-stud);
  margin-top: var(--b-s-beam); flex-wrap: wrap;
}
[data-design="b"] .b-step__nav:has(.b-tensor:only-child) { justify-content: flex-end; }
[data-design="b"] .b-tensor {
  font-family: var(--b-font-mono); text-transform: uppercase; letter-spacing: 0.08em;
  font-size: 12px; padding: 12px 18px; min-height: 44px; border-radius: var(--b-r-edge);
  cursor: pointer; border: 1px solid var(--b-hairline); background: transparent; color: var(--b-ink);
  transition: all var(--b-d-quick) var(--b-ease-register);
}
[data-design="b"] .b-tensor--primary { background: var(--b-orange); color: var(--b-bg); border-color: var(--b-orange); }
[data-design="b"] .b-tensor--primary:hover { background: color-mix(in oklab, var(--b-orange), black 8%); }
[data-design="b"] .b-tensor--secondary:hover { border-color: var(--b-orange); color: var(--b-orange); }
[data-design="b"] .b-tensor:focus-visible {
  outline: none; box-shadow: 0 0 0 3px color-mix(in oklab, var(--b-orange), transparent 70%);
}
[data-design="b"] .b-tensor:active { transform: translateY(1px); }
[data-design="b"] .b-summary {
  margin-top: var(--b-s-beam);
  display: grid; grid-template-columns: max-content 1fr; gap: var(--b-s-stud) var(--b-s-beam);
  border-top: 1px solid var(--b-hairline); padding-top: var(--b-s-beam);
}
[data-design="b"] .b-summary dt {
  font-family: var(--b-font-mono); text-transform: uppercase; letter-spacing: 0.08em;
  font-size: 11px; color: var(--b-stone);
}
[data-design="b"] .b-summary dd {
  font-family: var(--b-font-mono); font-size: 14px; color: var(--b-ink); margin: 0;
}
[data-design="b"] .b-funnel__foot {
  margin-top: var(--b-s-beam);
  font-family: var(--b-font-mono); font-size: 12px; letter-spacing: 0.03em;
  color: var(--b-stone);
}
[data-design="b"] .b-inline-link { color: var(--b-orange); text-decoration: none; border-bottom: 1px solid currentColor; }

/* ============================================================
   ambient A — services / capabilities (isobars)
   ============================================================ */
[data-design="b"] .b-ambient-a {
  position: relative; isolation: isolate; overflow: hidden;
  padding-block: var(--b-s-frame); background: var(--b-bg);
}
[data-design="b"] .b-ambient-a__motion { position: absolute; inset: 0; z-index: 0; opacity: 0.35; pointer-events: none; }
[data-design="b"] .b-ambient-a__motion svg { width: 100%; height: 100%; display: block; }
[data-design="b"] .b-isobar {
  fill: none; stroke: var(--b-cyan); stroke-width: .9; vector-effect: non-scaling-stroke;
  stroke-dasharray: 4 6;
  animation: b-isobar-flow 16s linear infinite;
  animation-delay: calc(var(--i, 0) * -2s);
  animation-play-state: paused;
}
[data-design="b"] .b-ambient-a.is-live .b-isobar { animation-play-state: running; }
@keyframes b-isobar-flow {
  0%   { stroke-dashoffset: 0;   transform: translateX(0); }
  50%  { stroke-dashoffset: -40; transform: translateX(-12px); }
  100% { stroke-dashoffset: -80; transform: translateX(0); }
}
[data-design="b"] .b-ambient-a__content {
  position: relative; z-index: 1; max-width: 1100px; margin-inline: auto;
  padding-inline: clamp(16px, 4vw, 36px);
}
[data-design="b"] .b-methods { display: flex; flex-direction: column; margin-top: var(--b-s-span); }
[data-design="b"] .b-method {
  display: grid; grid-template-columns: 80px 1fr; gap: var(--b-s-beam);
  padding: var(--b-s-beam) 0; border-top: 1px solid var(--b-hairline);
  transition: border-color var(--b-d-base) var(--b-ease-register);
}
[data-design="b"] .b-method:last-child { border-bottom: 1px solid var(--b-hairline); }
[data-design="b"] .b-method:hover { border-top-color: var(--b-orange); }
[data-design="b"] .b-method__num { font-family: var(--b-font-mono); color: var(--b-orange); font-size: 26px; letter-spacing: 0.04em; }
[data-design="b"] .b-method h3 {
  font-family: var(--b-font-display); font-size: 24px; font-weight: 500;
  margin-bottom: var(--b-s-rivet); color: var(--b-ink); letter-spacing: -0.01em;
}
[data-design="b"] .b-method p { color: var(--b-graphite); max-width: 60ch; line-height: 1.5; }

/* ============================================================
   ambient B — process / about (soap-film membrane)
   ============================================================ */
[data-design="b"] .b-ambient-b {
  position: relative; isolation: isolate; overflow: hidden;
  padding-block: var(--b-s-frame); background: var(--b-surface);
  border-block: 1px solid var(--b-mist);
}
[data-design="b"] .b-ambient-b__content {
  position: relative; z-index: 1; max-width: 1100px; margin-inline: auto;
  padding-inline: clamp(16px, 4vw, 36px);
}
[data-design="b"] .b-studio {
  display: grid; grid-template-columns: 1.6fr 1fr; gap: var(--b-s-span);
  align-items: start; margin-top: var(--b-s-span);
}
[data-design="b"] .b-studio__copy { font-size: 18px; line-height: 1.6; color: var(--b-graphite); max-width: 60ch; }
[data-design="b"] .b-phases { list-style: none; padding: 0; margin-top: var(--b-s-beam); }
[data-design="b"] .b-phases li {
  display: flex; align-items: baseline; gap: var(--b-s-stud);
  padding: var(--b-s-stud) 0; border-top: 1px solid var(--b-mist);
  font-size: 16px; color: var(--b-ink);
}
[data-design="b"] .b-phases__num { font-family: var(--b-font-mono); color: var(--b-orange); font-size: 13px; }
[data-design="b"] .b-studio__data { position: relative; border: 1px solid var(--b-hairline); border-radius: var(--b-r-edge); padding: var(--b-s-beam); background: var(--b-bg); }
[data-design="b"] .b-studio__data[data-corners="ticks"]::before,
[data-design="b"] .b-studio__data[data-corners="ticks"]::after {
  content: ""; position: absolute; width: 8px; height: 8px; border: 1px solid var(--b-orange);
}
[data-design="b"] .b-studio__data[data-corners="ticks"]::before { top: 8px; left: 8px; border-right: 0; border-bottom: 0; }
[data-design="b"] .b-studio__data[data-corners="ticks"]::after { bottom: 8px; right: 8px; border-left: 0; border-top: 0; }
[data-design="b"] .b-data-list { display: flex; flex-direction: column; border-top: 1px solid var(--b-hairline); }
[data-design="b"] .b-data-list > div {
  display: grid; grid-template-columns: 1fr auto; gap: var(--b-s-stud);
  padding: var(--b-s-stud) 0; border-bottom: 1px solid var(--b-mist);
}
[data-design="b"] .b-data-list dt {
  font-family: var(--b-font-mono); text-transform: uppercase; letter-spacing: 0.08em;
  font-size: 11px; color: var(--b-stone);
}
[data-design="b"] .b-data-list dd {
  font-family: var(--b-font-mono); font-size: 14px; color: var(--b-ink); margin: 0;
  font-variant-numeric: tabular-nums; text-align: right;
}
[data-design="b"] .b-ambient-b__motion { position: absolute; inset: 0; z-index: 0; opacity: 0.18; pointer-events: none; }
[data-design="b"] .b-ambient-b__motion svg { width: 100%; height: 100%; display: block; }
[data-design="b"] .b-mb { fill: none; stroke: var(--b-ink); stroke-width: .75; vector-effect: non-scaling-stroke; }
[data-design="b"] .b-mb__node { fill: var(--b-ink); }
[data-design="b"] .b-mb__node--accent { fill: var(--b-orange); }
[data-design="b"] .b-ambient-b.is-live .b-membrane {
  animation: b-membrane-breathe 20s var(--b-ease-settle) infinite alternate; transform-origin: center;
}
@keyframes b-membrane-breathe {
  0%   { transform: translateY(0) scale(1); }
  33%  { transform: translateY(-6px) scale(1.008); }
  66%  { transform: translateY(3px) scale(0.996); }
  100% { transform: translateY(-2px) scale(1.004); }
}

/* repeated CTA band */
[data-design="b"] .b-recta {
  display: flex; justify-content: center;
  padding: var(--b-s-frame) clamp(16px, 4vw, 36px);
  background: var(--b-bg); border-top: 1px solid var(--b-mist);
}

/* ============================================================
   FOOTER — drafting title block
   ============================================================ */
[data-design="b"] .b-footer {
  background: var(--b-bg); border-top: 1px solid var(--b-hairline);
  padding: var(--b-s-frame) clamp(16px, 4vw, 36px) var(--b-s-span);
}
[data-design="b"] .b-footer__beam {
  height: 1px; background: var(--b-hairline); max-width: 1100px; margin: 0 auto var(--b-s-span);
  background-image: repeating-linear-gradient(90deg, var(--b-orange) 0 2px, transparent 2px 192px);
}
[data-design="b"] .b-footer__cols {
  max-width: 1100px; margin-inline: auto;
  display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--b-s-span);
}
[data-design="b"] .b-footer__firm { font-family: var(--b-font-display); font-size: 18px; font-weight: 600; color: var(--b-ink); margin-bottom: var(--b-s-stud); }
[data-design="b"] .b-footer__label {
  font-family: var(--b-font-mono); text-transform: uppercase; letter-spacing: 0.12em;
  font-size: 11px; color: var(--b-orange); margin-bottom: var(--b-s-stud);
}
[data-design="b"] .b-footer__line { font-size: 15px; color: var(--b-graphite); margin-bottom: var(--b-s-rivet); line-height: 1.5; }
[data-design="b"] .b-footer__mono { font-family: var(--b-font-mono); font-size: 12px; letter-spacing: 0.04em; color: var(--b-stone); }

/* ============================================================
   responsive
   ============================================================ */
@media (max-width: 768px) {
  [data-design="b"] .b-method { grid-template-columns: 1fr; gap: var(--b-s-stud); }
  [data-design="b"] .b-method__num { font-size: 20px; }
  [data-design="b"] .b-studio { grid-template-columns: 1fr; gap: var(--b-s-beam); }
  [data-design="b"] .b-footer__cols { grid-template-columns: 1fr; gap: var(--b-s-beam); }
}
@media (max-width: 560px) {
  [data-design="b"] .b-header__bar { padding-block: 10px; }
  [data-design="b"] .b-logo__mark { font-size: 16px; }
  [data-design="b"] .b-drawer { inset: 56px 0 0 0; }
  [data-design="b"] .b-options { grid-template-columns: 1fr; }
  [data-design="b"] .b-members { grid-template-columns: 1fr; }
  [data-design="b"] .b-funnel { padding: var(--b-s-beam); min-height: 340px; }
  [data-design="b"] .b-beam__ticks { font-size: 8px; letter-spacing: 0.02em; }
  [data-design="b"] .b-beam__ticks li span { margin-right: 3px; }
}

@media (prefers-reduced-motion: reduce) {
  [data-design="b"] .b-chain__curve,
  [data-design="b"] .b-iso,
  [data-design="b"] .b-cat,
  [data-design="b"] .b-cat__load,
  [data-design="b"] .b-isobar,
  [data-design="b"] .b-ambient-b.is-live .b-membrane,
  [data-design="b"] .b-cta,
  [data-design="b"] .b-pointer__rule,
  [data-design="b"] .b-pointer__label,
  [data-design="b"] .b-step,
  [data-design="b"] .b-step.is-leaving { animation: none; }
  [data-design="b"] .b-beam__fill { transition: none; }
  [data-design="b"] .b-cta__cable-line,
  [data-design="b"] .b-cta__cable-head { transition: none; }
  /* keep catenaries visibly sagged (structure preserved at rest) */
  [data-design="b"] .b-cat { transform: scaleY(1.1); }
  [data-design="b"] .b-pointer__rule { transform: scaleY(1); opacity: .7; }
  [data-design="b"] .b-pointer__label { opacity: .8; }
}

/* ============================================================
   MOBILE OVERFLOW GUARDS (mandatory, appended at bottom)
   ============================================================ */
[data-design="b"].dq-design,
[data-design="b"] .dq-design { max-width: 100%; overflow-x: clip; }
[data-design="b"] * { min-width: 0; }
[data-design="b"] img,
[data-design="b"] svg:not([data-keep-size]) { max-width: 100%; height: auto; }

/* Phase-3.4 hero visibility floor (forge_assemble) */
[data-design="b"] [data-mf-role="hero"] :is(h1,h2,p,.headline,.subtitle,.proof,[class*="headline"],[class*="subtitle"],[class*="proof"]),
[data-design="b"] [data-mf-role="cta"] { opacity: 1 !important; }