:root {
  --ink: #0e1114;
  --ink-soft: #3a424a;
  --paper: #f6f7f8;
  --paper-2: #eef0f2;
  --steel: #3d6b6f;
  --steel-deep: #2a4d50;
  --steel-bright: #5a8a8e;
  --line: #d5d9de;
  --line-strong: #b8bec4;
  --surface: #ffffff;
  --ok: #1f6b4a;
  --err: #9b1c1c;
  --radius: 1px;
  --max: 1120px;
  --header-h: 3.75rem;
  --font-display: "Bricolage Grotesque", "Avenir Next", "Segoe UI", sans-serif;
  --font-body: "Manrope", "Avenir Next", "Segoe UI", sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, monospace;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(900px 420px at 100% -8%, rgba(61, 107, 111, 0.07), transparent 58%),
    var(--paper);
  font-family: var(--font-body);
  font-size: 1.02rem;
  line-height: 1.5;
  letter-spacing: -0.005em;
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: inherit;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
}

a:hover {
  color: var(--steel-deep);
}

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

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--ink);
  color: #fff;
  padding: 0.55rem 0.9rem;
  z-index: 1000;
  font-weight: 600;
}

.skip-link:focus {
  left: 1rem;
  top: 1rem;
}

.wrap {
  width: min(var(--max), calc(100% - 2.25rem));
  margin-inline: auto;
}

/* —— Header / chrome —— */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  height: var(--header-h);
  backdrop-filter: blur(10px);
  background: rgba(246, 247, 248, 0.92);
  border-bottom: 1px solid transparent;
  transition: border-color 220ms var(--ease), background 220ms var(--ease);
}

.site-header.is-scrolled {
  border-bottom-color: var(--line);
  background: rgba(246, 247, 248, 0.97);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  height: var(--header-h);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.12rem;
  letter-spacing: -0.035em;
  text-decoration: none;
  color: var(--ink);
}

.brand:hover {
  color: var(--ink);
}

.brand-mark {
  width: 1.35rem;
  height: 1.35rem;
  background:
    linear-gradient(var(--ink) 0 38%, transparent 38% 62%, var(--ink) 62% 100%),
    linear-gradient(90deg, var(--ink) 0 38%, transparent 38% 62%, var(--ink) 62% 100%),
    var(--steel);
  background-size: 100% 100%, 100% 100%, 100% 100%;
  background-repeat: no-repeat;
  clip-path: polygon(0 0, 100% 0, 100% 100%, 0 100%);
  box-shadow: inset 0 0 0 1px var(--ink);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.15rem 1rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  text-decoration: none;
  font-size: 0.88rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--ink-soft);
  padding: 0.35rem 0;
  border-bottom: 1px solid transparent;
}

.nav-links a[aria-current="page"] {
  color: var(--ink);
  border-bottom-color: var(--steel);
}

.nav-links a:hover {
  color: var(--ink);
}

.nav-links .btn {
  margin-left: 0.35rem;
  min-height: 2.35rem;
  padding: 0.45rem 0.9rem;
  font-size: 0.86rem;
}

.nav-toggle {
  display: none;
  border: 1px solid var(--line-strong);
  background: var(--surface);
  color: var(--ink);
  padding: 0.4rem 0.65rem;
  font: inherit;
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  cursor: pointer;
}

/* —— Buttons —— */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  min-height: 2.7rem;
  padding: 0.65rem 1.1rem;
  border: 1px solid transparent;
  border-radius: var(--radius);
  font: inherit;
  font-size: 0.92rem;
  font-weight: 700;
  letter-spacing: -0.015em;
  text-decoration: none;
  cursor: pointer;
  transition: background 160ms var(--ease), color 160ms var(--ease), border-color 160ms var(--ease);
}

.btn:hover {
  transform: none;
}

.btn:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--ink);
  color: #fff;
  border-color: var(--ink);
}

.btn-primary:hover {
  background: var(--steel-deep);
  border-color: var(--steel-deep);
  color: #fff;
}

.btn-secondary {
  background: transparent;
  border-color: var(--ink);
  color: var(--ink);
}

.btn-secondary:hover {
  background: var(--ink);
  color: #fff;
}

.btn-light {
  background: var(--surface);
  color: var(--ink);
  border-color: var(--surface);
}

.btn-light:hover {
  background: var(--paper-2);
  color: var(--ink);
}

.btn-steel {
  background: var(--steel);
  color: #fff;
  border-color: var(--steel);
}

.btn-steel:hover {
  background: var(--steel-bright);
  border-color: var(--steel-bright);
  color: #fff;
}

.btn-ghost {
  background: transparent;
  border-color: rgba(246, 247, 248, 0.42);
  color: var(--paper);
}

.btn-ghost:hover {
  background: rgba(246, 247, 248, 0.08);
  border-color: var(--paper);
  color: #fff;
}

.btn-nav {
  background: transparent;
  border: 1px solid rgba(246, 247, 248, 0.35);
  color: var(--paper);
  min-height: 2.2rem;
  padding: 0.4rem 0.85rem;
  font-size: 0.82rem;
}

.btn-nav:hover {
  background: var(--steel);
  border-color: var(--steel);
  color: #fff;
}

.section-dark .btn-secondary {
  border-color: rgba(246, 247, 248, 0.55);
  color: var(--paper);
}

.section-dark .btn-secondary:hover {
  background: var(--paper);
  border-color: var(--paper);
  color: var(--ink);
}

/* —— Home chrome (HVACOpsHQ lessons, BuildWorkflow brand) —— */
.utility-bar {
  background: var(--ink);
  color: rgba(246, 247, 248, 0.72);
  font-size: 0.78rem;
  font-weight: 500;
  letter-spacing: 0.01em;
}

.utility-bar-inner {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  min-height: 2rem;
}

.utility-bar a {
  color: rgba(246, 247, 248, 0.88);
  text-decoration: none;
}

.utility-bar a:hover {
  color: #fff;
}

.utility-sep {
  width: 1px;
  height: 0.85rem;
  background: rgba(246, 247, 248, 0.22);
}

.page-home .site-header--light {
  background: rgba(255, 255, 255, 0.96);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(10px);
}

.page-home .site-header--light.is-scrolled {
  background: rgba(255, 255, 255, 0.98);
  box-shadow: 0 8px 24px rgba(14, 17, 20, 0.06);
}

.page-home .site-header--light .brand,
.page-home .site-header--light .nav-links a {
  color: var(--ink-soft);
}

.page-home .site-header--light .brand {
  color: var(--ink);
}

.page-home .site-header--light .nav-links a:hover,
.page-home .site-header--light .nav-links a[aria-current="page"] {
  color: var(--ink);
}

.page-home .site-header--light .nav-links a[aria-current="page"] {
  border-bottom-color: var(--steel);
}

.btn-nav-cta {
  margin-left: 0.35rem;
  min-height: 2.25rem;
  padding: 0.4rem 0.9rem;
  font-size: 0.84rem;
  background: var(--steel);
  border-color: var(--steel);
  color: #fff;
}

.btn-nav-cta:hover {
  background: var(--steel-deep);
  border-color: var(--steel-deep);
  color: #fff;
}

/* —— Ops-system homepage —— */
.hero {
  padding: 0;
  position: relative;
}

.hero--ops {
  padding: 0;
}

.hero-ops {
  position: relative;
  min-height: clamp(32rem, 74svh, 42rem);
  display: flex;
  align-items: center;
  color: #fff;
  background:
    radial-gradient(ellipse 55% 50% at 82% 45%, rgba(61, 107, 111, 0.32), transparent 65%),
    linear-gradient(160deg, #12171b 0%, var(--ink) 52%, #090b0d 100%),
    linear-gradient(rgba(246, 247, 248, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(246, 247, 248, 0.03) 1px, transparent 1px);
  background-size: auto, auto, 44px 44px, 44px 44px;
  overflow: hidden;
}

.hero-ops::after {
  content: "";
  position: absolute;
  inset: auto 0 0 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(90, 138, 142, 0.55), transparent);
}

.hero-ops-grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 2.5rem;
  align-items: center;
  padding: 3.5rem 0 3.25rem;
}

.hero--ops .hero-copy {
  padding: 0;
  border: none;
  animation: rise-in 700ms var(--ease) both;
}

.hero-brand {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.15rem, 2vw, 1.4rem);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin: 0 0 1.1rem;
  color: rgba(246, 247, 248, 0.72);
}

.hero--ops h1 {
  color: #fff;
  max-width: 11ch;
  font-size: clamp(2.7rem, 6vw, 4.4rem);
  line-height: 0.96;
  margin-bottom: 1.1rem;
}

.hero--ops h1 .accent {
  color: var(--steel-bright);
}

.hero--ops .lede {
  color: rgba(246, 247, 248, 0.74);
  max-width: 30rem;
  font-size: 1.08rem;
  margin-bottom: 1.6rem;
}

.hero--ops .cta-row {
  margin-bottom: 0;
}

.chain-board {
  background: rgba(10, 12, 14, 0.55);
  border: 1px solid rgba(246, 247, 248, 0.14);
  padding: 1.35rem 1.25rem 1.2rem;
  backdrop-filter: blur(8px);
  animation: rise-in 900ms var(--ease) 80ms both;
}

.chain-label {
  margin: 0 0 1rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--steel-bright);
}

.ops-chain {
  display: flex;
  align-items: stretch;
  gap: 0;
  flex-wrap: wrap;
}

.chain-node {
  flex: 1 1 5.5rem;
  min-width: 5.2rem;
  padding: 0.95rem 0.75rem;
  background: rgba(246, 247, 248, 0.04);
  border: 1px solid rgba(246, 247, 248, 0.12);
  display: grid;
  gap: 0.35rem;
}

.chain-node.is-break {
  background: rgba(61, 107, 111, 0.28);
  border-color: var(--steel-bright);
  box-shadow: 0 0 0 1px rgba(90, 138, 142, 0.35), 0 12px 28px rgba(0, 0, 0, 0.25);
}

.chain-code {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: rgba(246, 247, 248, 0.5);
}

.chain-node.is-break .chain-code {
  color: var(--steel-bright);
}

.chain-node strong {
  font-family: var(--font-display);
  font-size: 1.05rem;
  letter-spacing: -0.03em;
  color: #fff;
}

.chain-join {
  width: 1.1rem;
  align-self: center;
  height: 1px;
  background: linear-gradient(90deg, rgba(246, 247, 248, 0.15), rgba(90, 138, 142, 0.7), rgba(246, 247, 248, 0.15));
  position: relative;
}

.chain-join::after {
  content: "";
  position: absolute;
  right: -1px;
  top: -3px;
  border: 4px solid transparent;
  border-left-color: rgba(90, 138, 142, 0.75);
}

.chain-caption {
  margin: 1rem 0 0;
  color: rgba(246, 247, 248, 0.58);
  font-size: 0.88rem;
  line-height: 1.45;
}

.section-head--wide {
  max-width: 44rem;
}

.section-ink {
  background: var(--ink);
  color: var(--paper);
  border-block: 1px solid #1a1f24;
}

.section-ink .eyebrow {
  color: var(--steel-bright);
}

.section-ink .eyebrow::before {
  background: var(--steel-bright);
}

.section-ink .lede {
  color: rgba(246, 247, 248, 0.68);
}

.break-grid,
.method-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
}

.method-grid {
  grid-template-columns: repeat(4, 1fr);
}

.break-tile,
.method-tile {
  position: relative;
  padding: 1.5rem 1.25rem 1.4rem;
  background: var(--surface);
  border: 1px solid var(--line);
  box-shadow: 0 10px 28px rgba(14, 17, 20, 0.04);
  transition: border-color 180ms var(--ease), transform 180ms var(--ease), box-shadow 180ms var(--ease);
}

.break-tile:hover,
.method-tile:hover {
  border-color: var(--steel);
  transform: translateY(-2px);
  box-shadow: 0 16px 36px rgba(14, 17, 20, 0.08);
}

.break-num,
.method-num {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--steel);
  margin-bottom: 0.85rem;
  font-weight: 600;
}

.break-tile h3,
.method-tile h3 {
  margin-bottom: 0.45rem;
  font-size: 1.35rem;
}

.break-tile p,
.method-tile p {
  margin: 0;
  color: var(--ink-soft);
  font-size: 0.95rem;
  line-height: 1.45;
}

.process-rail {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 0.55rem;
}

.process-rail li {
  padding: 1.1rem 0.85rem;
  border: 1px solid rgba(246, 247, 248, 0.14);
  background: rgba(246, 247, 248, 0.04);
  display: grid;
  gap: 0.45rem;
  min-height: 5.5rem;
}

.process-rail span {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  color: var(--steel-bright);
}

.process-rail strong {
  font-family: var(--font-display);
  font-size: 1.05rem;
  letter-spacing: -0.03em;
  color: #fff;
}

.example-board {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.55rem;
  padding: 1.25rem;
  background: var(--paper-2);
  border: 1px solid var(--line);
}

.example-step {
  flex: 1 1 7rem;
  min-width: 6.5rem;
  padding: 1rem 0.85rem;
  background: var(--surface);
  border: 1px solid var(--line);
  text-align: center;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.example-step.is-focus {
  background: var(--ink);
  border-color: var(--ink);
  color: #fff;
  box-shadow: 0 12px 28px rgba(14, 17, 20, 0.18);
}

.example-arrow {
  width: 1.25rem;
  height: 1px;
  background: var(--steel);
  position: relative;
  flex: 0 0 1.25rem;
}

.example-arrow::after {
  content: "";
  position: absolute;
  right: -1px;
  top: -3px;
  border: 4px solid transparent;
  border-left-color: var(--steel);
}

.tool-moment {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 0;
  border: 1px solid var(--line);
  background: var(--surface);
  overflow: hidden;
  box-shadow: 0 18px 48px rgba(14, 17, 20, 0.06);
}

.tool-moment-copy {
  padding: 2rem 1.75rem;
}

.tool-moment-copy .lede {
  margin-bottom: 1.25rem;
}

.tool-moment-panel {
  display: grid;
  gap: 0;
  background: var(--ink);
  color: #fff;
  padding: 0.85rem;
}

.tool-metric {
  padding: 1rem 1rem 0.95rem;
  border: 1px solid rgba(246, 247, 248, 0.1);
  display: grid;
  gap: 0.35rem;
}

.tool-metric + .tool-metric {
  margin-top: 0.55rem;
}

.tool-metric span {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: rgba(246, 247, 248, 0.5);
}

.tool-metric strong {
  font-family: var(--font-display);
  font-size: 1.55rem;
  letter-spacing: -0.03em;
}

.tool-metric.is-accent {
  background: rgba(61, 107, 111, 0.28);
  border-color: rgba(90, 138, 142, 0.55);
}

.tool-metric.is-accent span {
  color: var(--steel-bright);
}

.section-final {
  padding: 4rem 0;
}

.final-cta {
  max-width: 36rem;
}

.final-cta h2 {
  font-size: clamp(2rem, 4vw, 3rem);
  margin-bottom: 0.75rem;
  color: #fff;
}

.final-cta .lede {
  margin-bottom: 1.4rem;
}

@keyframes rise-in {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin: 0 0 0.85rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--steel-deep);
  font-weight: 600;
}

.eyebrow::before {
  content: "";
  width: 1.15rem;
  height: 1px;
  background: var(--steel);
}

h1,
h2,
h3 {
  font-family: var(--font-display);
  letter-spacing: -0.035em;
  line-height: 1.05;
  margin: 0 0 0.75rem;
  font-weight: 800;
}

h1 {
  font-size: clamp(2.15rem, 4.6vw, 3.55rem);
  max-width: 16ch;
}

h2 {
  font-size: clamp(1.55rem, 2.8vw, 2.25rem);
}

h3 {
  font-size: 1.12rem;
  letter-spacing: -0.025em;
}

.lede {
  max-width: 38rem;
  font-size: 1.05rem;
  line-height: 1.55;
  color: var(--ink-soft);
  margin: 0 0 1.35rem;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
  margin-bottom: 1.15rem;
}

.fine {
  margin: 0;
  color: #6a727a;
  font-size: 0.88rem;
  line-height: 1.45;
  max-width: 36rem;
}

/* —— Sections —— */
.section {
  padding: 3.5rem 0;
}

.section-tight {
  padding: 2.25rem 0 3.5rem;
}

.section-dark {
  background: var(--ink);
  color: var(--paper);
  border-block: 1px solid #1a1f24;
}

.section-dark .lede,
.section-dark p,
.section-dark .fine {
  color: rgba(246, 247, 248, 0.72);
}

.section-dark .eyebrow {
  color: var(--steel-bright);
}

.section-dark .eyebrow::before {
  background: var(--steel-bright);
}

.section-band {
  background: var(--paper-2);
  border-block: 1px solid var(--line);
}

.section-head {
  display: grid;
  gap: 0.55rem;
  margin-bottom: 1.75rem;
  max-width: 40rem;
}

.section-head .lede {
  margin-bottom: 0;
}

.grid-3,
.grid-2 {
  display: grid;
  gap: 0;
}

.grid-3 {
  grid-template-columns: repeat(3, 1fr);
  border: 1px solid var(--line);
}

.grid-2 {
  grid-template-columns: repeat(2, 1fr);
  border: 1px solid var(--line);
}

.grid-3 > *,
.grid-2 > * {
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.grid-3 > *:nth-child(3n),
.grid-2 > *:nth-child(2n) {
  border-right: none;
}

.section-dark .grid-2 {
  border-color: rgba(246, 247, 248, 0.14);
}

.section-dark .grid-2 > * {
  border-right-color: rgba(246, 247, 248, 0.12);
  border-bottom-color: rgba(246, 247, 248, 0.12);
}

/* —— Ops modules —— */
.card,
.panel,
.wf-cell {
  background: var(--surface);
  border: 1px solid var(--line);
  padding: 1.15rem 1.15rem 1.25rem;
  box-shadow: none;
}

.grid-3 .card,
.grid-2 .card {
  border: none;
  border-radius: 0;
}

.section-dark .card {
  background: transparent;
  border: none;
  color: var(--paper);
}

.section-dark .card p {
  color: rgba(246, 247, 248, 0.7);
}

.panel h3 {
  margin-bottom: 0.45rem;
}

.panel p {
  margin: 0;
  color: var(--ink-soft);
}

.ops-panel {
  border: 1px solid var(--line);
  background: var(--surface);
  padding: 1.25rem 1.2rem;
}

.ops-panel h3 + h3 {
  margin-top: 1.15rem;
}

.kicker {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--steel-deep);
  margin: 0 0 0.45rem;
  font-weight: 600;
}

.section-dark .kicker {
  color: var(--steel-bright);
}

.flow-rail {
  display: grid;
  gap: 0;
  border: 1px solid rgba(246, 247, 248, 0.14);
}

.hero-plane .flow-rail {
  border-color: rgba(246, 247, 248, 0.16);
}

.flow-step {
  display: grid;
  grid-template-columns: 2.1rem 1fr;
  gap: 0.75rem;
  align-items: start;
  padding: 0.8rem 0.85rem;
  border-bottom: 1px solid rgba(246, 247, 248, 0.12);
  background: transparent;
  transition: background 200ms var(--ease);
}

.flow-step:last-child {
  border-bottom: none;
}

.flow-step.is-active {
  background: rgba(90, 138, 142, 0.12);
}

.flow-step strong {
  display: block;
  font-family: var(--font-display);
  font-weight: 700;
  margin-bottom: 0.1rem;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.flow-step span:not(.flow-num) {
  color: rgba(246, 247, 248, 0.68);
  font-size: 0.9rem;
  line-height: 1.4;
}

.flow-num {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--steel-bright);
  min-width: 2rem;
  padding-top: 0.15rem;
  font-weight: 600;
}

.workflow-map {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0;
  border: 1px solid var(--line);
}

.wf-cell {
  min-height: 10rem;
  border: none;
  border-right: 1px solid var(--line);
  position: relative;
  background: var(--surface);
}

.wf-cell:last-child {
  border-right: none;
}

.wf-cell::after {
  content: "";
  position: absolute;
  right: -1px;
  top: 1.35rem;
  width: 7px;
  height: 1px;
  background: var(--steel);
  z-index: 1;
}

.wf-cell:last-child::after {
  content: none;
}

.list-clean {
  margin: 0;
  padding-left: 1.05rem;
  color: var(--ink-soft);
}

.list-clean li + li {
  margin-top: 0.4rem;
}

.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.75rem;
  align-items: start;
}

.quote-block {
  border-left: 2px solid var(--steel);
  padding: 0.15rem 0 0.15rem 0.95rem;
  margin: 1.1rem 0 0;
  color: var(--ink-soft);
  font-size: 0.98rem;
}

.table-like {
  width: 100%;
  border-collapse: collapse;
  border: 1px solid var(--line);
  background: var(--surface);
}

.table-like th,
.table-like td {
  text-align: left;
  vertical-align: top;
  padding: 0.8rem 0.85rem;
  border-bottom: 1px solid var(--line);
}

.table-like tr:last-child th,
.table-like tr:last-child td {
  border-bottom: none;
}

.table-like th {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--steel-deep);
  width: 8rem;
  background: var(--paper-2);
  font-weight: 600;
}

.cta-slab {
  border: 1px solid var(--line);
  background: var(--surface);
  padding: 1.5rem 1.4rem;
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 1.25rem;
  align-items: center;
}

/* —— Change Order Calculator · Industrial instrument —— */
.page-calc .hero,
.calc-hero {
  padding: 2.25rem 0 1.25rem;
}

.calc-hero-inner {
  display: grid;
  gap: 1.25rem;
  align-items: end;
}

.calc-hero-lede {
  margin: 0;
  max-width: 36rem;
}

.calc-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.45rem;
}

.calc-step {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  margin: 0;
  padding: 0.55rem 0.65rem;
  border: 1px solid var(--line);
  background: var(--surface);
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: #6a727a;
  font-weight: 600;
}

.calc-step span {
  color: var(--steel-deep);
}

.calc-step.is-active,
.calc-step.is-done {
  border-color: var(--steel);
  color: var(--ink);
  background: color-mix(in srgb, var(--paper) 78%, var(--steel) 22%);
}

.calc-band {
  padding-top: 0.5rem;
}

.calc-toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1rem;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1rem;
}

.calc-toolbar-note {
  margin: 0;
  flex: 1 1 16rem;
  padding: 0.65rem 0.8rem;
  border: 1px solid var(--steel);
  background: color-mix(in srgb, var(--paper) 70%, var(--steel) 30%);
  font-size: 0.9rem;
  color: var(--ink);
}

.calc-toolbar-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.calc-workstation {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(18rem, 0.8fr);
  gap: 1.15rem;
  align-items: start;
}

.calc-workspace {
  display: grid;
  gap: 0.9rem;
  margin: 0;
  padding: 0;
  background: transparent;
  border: 0;
  box-shadow: none;
}

.calc-card {
  background: var(--surface);
  border: 1px solid var(--line-strong);
  padding: 1.1rem 1.05rem 1.15rem;
}

.calc-card-head {
  display: flex;
  gap: 0.85rem;
  align-items: flex-start;
  margin-bottom: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--line);
}

.calc-stage-num {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--steel-deep);
  min-width: 1.6rem;
}

.calc-card-head h2 {
  margin: 0;
  font-size: 1.2rem;
  letter-spacing: -0.02em;
}

.calc-card-sub {
  margin: 0.2rem 0 0;
  color: var(--ink-soft);
  font-size: 0.9rem;
}

.calc-field-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.8rem 0.95rem;
}

.calc-row-full {
  margin-bottom: 0.85rem;
}

.field-tag {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: #6a727a;
  font-weight: 600;
}

.unit-field {
  display: flex;
  align-items: stretch;
  border: 1px solid var(--line-strong);
  background: var(--paper);
  min-height: 2.55rem;
}

.unit-field:focus-within {
  border-color: var(--steel);
  outline: 2px solid color-mix(in srgb, var(--steel) 45%, transparent);
  outline-offset: 1px;
}

.unit-prefix,
.unit-suffix {
  display: inline-flex;
  align-items: center;
  padding: 0 0.65rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--steel-deep);
  background: color-mix(in srgb, var(--paper-2) 80%, var(--steel) 20%);
  border: 0;
  white-space: nowrap;
}

.unit-field input {
  flex: 1;
  min-width: 0;
  border: 0 !important;
  background: transparent !important;
  box-shadow: none !important;
  outline: none !important;
  padding: 0.55rem 0.65rem;
  font-family: var(--font-mono);
  font-size: 0.95rem;
  font-weight: 500;
}

.calc-advanced {
  margin-top: 0.95rem;
  border-top: 1px dashed var(--line);
  padding-top: 0.75rem;
}

.calc-advanced summary {
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--steel-deep);
  font-weight: 600;
  list-style: none;
}

.calc-advanced summary::-webkit-details-marker {
  display: none;
}

.calc-advanced summary::before {
  content: "+ ";
}

.calc-advanced[open] summary::before {
  content: "− ";
}

.calc-advanced-grid {
  margin-top: 0.75rem;
}

.calc-bottleneck {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.45rem;
}

.calc-choice {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  margin: 0;
  padding: 0.6rem 0.7rem;
  border: 1px solid var(--line);
  background: var(--paper);
  cursor: pointer;
  font-size: 0.92rem;
}

.calc-choice:has(input:focus-visible) {
  outline: 2px solid var(--steel);
  outline-offset: 1px;
}

.calc-choice:has(input:checked) {
  border-color: var(--ink);
  background: color-mix(in srgb, var(--paper) 75%, var(--steel) 25%);
}

.calc-choice input {
  width: 1rem;
  height: 1rem;
  margin: 0;
  accent-color: var(--steel-deep);
}

.calc-rail {
  position: sticky;
  top: calc(var(--header-h) + 0.75rem);
}

.calc-rail-inner {
  background: var(--ink);
  color: #f2f4f5;
  border: 1px solid var(--ink);
  padding: 1.15rem 1.1rem 1.25rem;
}

.calc-rail-inner .kicker {
  color: var(--steel-bright);
}

.calc-rail-inner .hint {
  color: #a8b0b6;
}

.calc-empty {
  margin: 0.35rem 0 1rem;
  padding: 1rem 0.2rem 0.4rem;
  border: 0;
  background: transparent;
}

.calc-empty-title {
  margin: 0 0 0.35rem;
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.calc-empty-copy {
  margin: 0;
  color: #b7bec4;
}

.calc-primary {
  margin: 0.35rem 0 1rem;
  padding-bottom: 0.95rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.14);
}

.calc-secondary {
  margin-bottom: 1.1rem;
  padding-bottom: 0.95rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.14);
}

.calc-metric-label {
  margin: 0 0 0.25rem;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--steel-bright);
  font-weight: 600;
}

.calc-metric-value {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(1.55rem, 2.4vw, 2rem);
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1.1;
  color: #fff;
}

.calc-metric-value--sec {
  font-size: clamp(1.25rem, 2vw, 1.55rem);
  color: #e8ecee;
}

.calc-story-title,
.calc-panel-kicker,
.calc-bridge-kicker {
  margin: 0 0 0.55rem;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--steel-bright);
  font-weight: 600;
}

.calc-story {
  display: grid;
  gap: 0.85rem;
  margin-bottom: 1rem;
}

.calc-story-block {
  display: grid;
  gap: 0.35rem;
}

.calc-line {
  display: flex;
  justify-content: space-between;
  gap: 0.75rem;
  align-items: baseline;
  font-size: 0.9rem;
}

.calc-line span {
  color: #b8c0c6;
}

.calc-line strong {
  font-family: var(--font-mono);
  font-weight: 600;
  letter-spacing: -0.02em;
  color: #f4f6f7;
}

.calc-line--add span::before {
  content: "+ ";
  color: var(--steel-bright);
}

.calc-line--sum {
  margin-top: 0.25rem;
  padding-top: 0.4rem;
  border-top: 1px solid rgba(255, 255, 255, 0.18);
}

.calc-line--sum span,
.calc-line--sum strong {
  color: #fff;
  font-weight: 700;
}

.calc-line--muted span,
.calc-line--muted strong {
  color: #8d969d;
  font-size: 0.84rem;
}

.calc-panel {
  margin: 0 0 1rem;
  padding: 0.75rem 0 0;
  border-top: 1px solid rgba(255, 255, 255, 0.12);
}

.friction-line {
  margin: 0.2rem 0 0.35rem;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: -0.02em;
  color: #fff;
}

#out-profit.is-negative {
  color: #f0a8a8;
}

.is-flash {
  animation: calc-flash 0.55s ease;
}

@keyframes calc-flash {
  0% {
    color: var(--steel-bright);
  }
  100% {
    color: inherit;
  }
}

.calc-bridge {
  margin-top: 0.35rem;
  padding-top: 1rem;
  border-top: 1px solid rgba(255, 255, 255, 0.16);
}

.calc-bridge-copy {
  margin: 0 0 0.45rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  color: #c5ced4;
}

.calc-bridge-ask {
  margin: 0 0 0.85rem;
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.calc-bridge .btn-primary {
  background: #fff;
  color: var(--ink);
  border-color: #fff;
}

.calc-bridge .btn-primary:hover {
  background: var(--steel-bright);
  border-color: var(--steel-bright);
  color: var(--ink);
}

.calc-mobile-summary {
  display: none;
}

body.calc-demo-on .calc-workspace .unit-field,
body.calc-demo-on .calc-workspace input:not([type="radio"]) {
  box-shadow: inset 0 0 0 1px color-mix(in srgb, var(--steel) 35%, transparent);
}

@media (max-width: 960px) {
  .calc-workstation,
  .calc-field-grid,
  .calc-bottleneck,
  .calc-steps {
    grid-template-columns: 1fr;
  }

  .calc-rail {
    position: static;
  }

  .calc-mobile-summary {
    position: sticky;
    bottom: 0;
    z-index: 30;
    display: grid;
    grid-template-columns: 1fr 1fr auto;
    gap: 0.65rem;
    align-items: center;
    margin-top: 1rem;
    padding: 0.75rem 0.85rem;
    background: var(--ink);
    color: #fff;
    border: 1px solid var(--ink);
  }

  .calc-mobile-summary[hidden] {
    display: none !important;
  }

  .calc-mobile-label {
    margin: 0;
    font-family: var(--font-mono);
    font-size: 0.62rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--steel-bright);
  }

  .calc-mobile-value {
    margin: 0.1rem 0 0;
    font-family: var(--font-mono);
    font-size: 0.95rem;
    font-weight: 600;
  }

  .btn-compact {
    padding: 0.55rem 0.75rem;
    font-size: 0.82rem;
  }

  body.page-calc {
    padding-bottom: 4.5rem;
  }
}

@media (min-width: 961px) {
  .calc-hero-inner {
    grid-template-columns: 1.2fr 0.8fr;
  }
}

/* —— Form —— */
.form {
  display: grid;
  gap: 0.75rem;
  background: var(--surface);
  border: 1px solid var(--line);
  padding: 1.35rem 1.25rem;
  box-shadow: none;
}

.form.is-loading {
  opacity: 0.85;
  pointer-events: none;
}

.form-row {
  display: grid;
  gap: 0.28rem;
}

.form-row label {
  font-weight: 700;
  font-size: 0.84rem;
  letter-spacing: -0.01em;
}

.form-row .hint {
  color: #6a727a;
  font-size: 0.78rem;
}

.form-row input,
.form-row select,
.form-row textarea {
  width: 100%;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--paper);
  padding: 0.7rem 0.75rem;
  font: inherit;
  color: var(--ink);
  transition: border-color 140ms var(--ease), background 140ms var(--ease);
}

.form-row input:focus,
.form-row select:focus,
.form-row textarea:focus {
  outline: none;
  border-color: var(--steel);
  background: var(--surface);
}

.form-row textarea {
  min-height: 7rem;
  resize: vertical;
}

.hp {
  position: absolute;
  left: -10000px;
  opacity: 0;
  height: 0;
  width: 0;
  overflow: hidden;
}

.form-status {
  min-height: 1.25rem;
  font-weight: 600;
  font-size: 0.88rem;
}

.form-status.ok {
  color: var(--ok);
}

.form-status.err {
  color: var(--err);
}

.field-error {
  min-height: 1rem;
  color: var(--err);
  font-size: 0.78rem;
  font-weight: 600;
}

.form-success {
  border: 1px solid var(--steel);
  background: var(--ink);
  color: var(--paper);
  padding: 1.1rem 1rem;
  margin-top: 0.35rem;
}

.form-success strong {
  font-family: var(--font-display);
  letter-spacing: -0.02em;
  display: block;
  margin-bottom: 0.25rem;
}

.form-success[hidden] {
  display: none;
}

.form-success:focus {
  outline: 2px solid var(--steel-bright);
  outline-offset: 2px;
}

.form-success .receipt-meta {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  color: var(--steel-bright);
  margin-top: 0.55rem;
}

input[aria-invalid="true"],
textarea[aria-invalid="true"],
select[aria-invalid="true"] {
  border-color: var(--err);
  background: #fff8f8;
}

.contact-card {
  display: grid;
  gap: 0.75rem;
  margin-top: 1.15rem;
  border: 1px solid var(--line);
  padding: 1rem 1.05rem;
  background: var(--paper-2);
}

.contact-card a {
  font-weight: 700;
  text-decoration: none;
  font-size: 1.15rem;
  letter-spacing: -0.02em;
}

/* —— Footer —— */
.site-footer {
  border-top: 1px solid var(--line);
  padding: 2.25rem 0 1.75rem;
  background: var(--paper-2);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr;
  gap: 1.35rem;
}

.footer-grid h3 {
  font-size: 0.78rem;
  margin-bottom: 0.5rem;
  font-family: var(--font-mono);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  font-weight: 600;
  color: var(--steel-deep);
}

.footer-grid p,
.footer-grid a {
  color: #5a6168;
  text-decoration: none;
  font-size: 0.88rem;
}

.footer-grid a:hover {
  color: var(--ink);
}

.legal {
  margin-top: 1.35rem;
  padding-top: 0.9rem;
  border-top: 1px solid var(--line);
  color: #7a8188;
  font-size: 0.78rem;
}

/* —— Motion —— */
.hero-grid {
  opacity: 0;
  transform: translateY(10px);
  animation: hero-in 520ms var(--ease) 40ms forwards;
}

@keyframes hero-in {
  to {
    opacity: 1;
    transform: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .hero-grid {
    opacity: 1;
    transform: none;
    animation: none;
  }

  .site-header,
  .flow-step,
  .btn,
  .form-row input,
  .form-row textarea,
  .hero--ops .hero-copy,
  .chain-board,
  .break-tile,
  .method-tile {
    transition: none;
    animation: none !important;
  }
}

/* —— Responsive —— */
@media (max-width: 900px) {
  .hero-ops-grid,
  .hero-grid,
  .break-grid,
  .method-grid,
  .process-rail,
  .tool-moment,
  .grid-3,
  .grid-2,
  .workflow-map,
  .split,
  .footer-grid,
  .cta-slab {
    grid-template-columns: 1fr;
  }

  .hero-ops {
    min-height: auto;
  }

  .hero-ops-grid {
    gap: 1.75rem;
    padding: 2.5rem 0 2.25rem;
  }

  .hero--ops h1 {
    max-width: none;
  }

  .process-rail {
    grid-template-columns: repeat(2, 1fr);
  }

  .method-grid {
    grid-template-columns: 1fr 1fr;
  }

  .chain-join {
    display: none;
  }

  .ops-chain {
    gap: 0.45rem;
  }

  .example-arrow {
    display: none;
  }

  .page-home .site-header--light .nav-links {
    background: #fff;
  }

  .page-home .site-header--light .nav-links li {
    border-top-color: var(--line);
  }

  .hero-copy {
    border-right: none;
    border-bottom: none;
    padding: 0;
  }

  .grid-3 > *,
  .grid-2 > * {
    border-right: none;
  }

  .grid-3 > *:not(:last-child),
  .grid-2 > *:not(:last-child) {
    border-bottom: 1px solid var(--line);
  }

  .section-dark .grid-2 > *:not(:last-child) {
    border-bottom-color: rgba(246, 247, 248, 0.12);
  }

  .wf-cell {
    border-right: none;
    border-bottom: 1px solid var(--line);
  }

  .wf-cell:last-child {
    border-bottom: none;
  }

  .wf-cell::after {
    content: "";
    right: auto;
    left: 1.15rem;
    top: auto;
    bottom: -1px;
    width: 1px;
    height: 7px;
  }

  .nav-toggle {
    display: inline-flex;
  }

  .nav-links {
    display: none;
    position: fixed;
    left: 0;
    right: 0;
    top: var(--header-h);
    bottom: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: var(--paper);
    border-bottom: none;
    padding: 0.5rem 1.15rem 1.5rem;
    overflow-y: auto;
    z-index: 40;
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links li {
    border-top: 1px solid var(--line);
  }

  .nav-links a {
    display: block;
    padding: 0.95rem 0;
    border-bottom: none;
  }

  .nav-links .btn {
    margin: 0.85rem 0 0;
    width: 100%;
  }

  h1 {
    max-width: none;
  }

  body.nav-open {
    overflow: hidden;
  }
}