:root {
  --ink: #172124;
  --muted: #657174;
  --paper: #f7f4ec;
  --panel: #fffaf0;
  --line: #d8d0bf;
  --teal: #1f7d78;
  --teal-dark: #135c59;
  --coral: #d66045;
  --steel: #4e6673;
  --gold: #b58a3b;
  --shadow: 0 24px 70px rgba(23, 33, 36, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Microsoft YaHei", "PingFang SC", "Segoe UI", sans-serif;
  color: var(--ink);
  background:
    linear-gradient(90deg, rgba(31, 125, 120, 0.08) 1px, transparent 1px),
    linear-gradient(0deg, rgba(31, 125, 120, 0.06) 1px, transparent 1px),
    var(--paper);
  background-size: 32px 32px;
}

a {
  color: inherit;
  text-decoration: none;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 68px;
  padding: 0 5vw;
  border-bottom: 1px solid rgba(23, 33, 36, 0.12);
  background: rgba(247, 244, 236, 0.92);
  backdrop-filter: blur(14px);
}

.brand,
.nav {
  display: flex;
  align-items: center;
}

.brand {
  gap: 10px;
  min-width: 0;
  font-weight: 700;
  letter-spacing: 0;
}

.brand span:last-child {
  overflow-wrap: anywhere;
}

.brand-mark {
  width: 24px;
  height: 24px;
  border: 2px solid var(--teal);
  background:
    linear-gradient(90deg, transparent 45%, var(--teal) 45% 55%, transparent 55%),
    linear-gradient(0deg, transparent 45%, var(--teal) 45% 55%, transparent 55%);
}

.nav {
  gap: 18px;
  color: var(--muted);
  font-size: 14px;
}

.nav a {
  padding: 8px 0;
  border-bottom: 2px solid transparent;
}

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

.section-shell {
  width: min(1180px, 90vw);
  margin: 0 auto;
  padding: 86px 0;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(360px, 0.95fr);
  gap: 56px;
  align-items: center;
  min-height: calc(100vh - 68px);
  padding-top: 58px;
}

.eyebrow {
  margin: 0 0 14px;
  color: var(--teal-dark);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: 760px;
  margin-bottom: 24px;
  font-size: clamp(42px, 7vw, 78px);
  line-height: 1.05;
  letter-spacing: 0;
}

h2 {
  font-size: clamp(28px, 4vw, 48px);
  line-height: 1.15;
  letter-spacing: 0;
}

h3 {
  margin-bottom: 14px;
  font-size: 22px;
}

.lead {
  max-width: 680px;
  color: #445155;
  font-size: 19px;
  line-height: 1.85;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 34px;
}

.part-switch {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
  margin: 30px 0 4px;
}

.part-card {
  display: flex;
  min-height: 126px;
  flex-direction: column;
  justify-content: center;
  gap: 6px;
  padding: 18px;
  border: 1px solid rgba(23, 33, 36, 0.16);
  color: var(--ink);
  text-decoration: none;
  background: rgba(255, 250, 240, 0.78);
  box-shadow: 0 14px 34px rgba(38, 34, 28, 0.08);
}

.part-card span {
  color: var(--coral);
  font-size: 13px;
  font-weight: 900;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.part-card strong {
  font-size: 22px;
}

.part-card em {
  color: var(--muted);
  font-size: 14px;
  font-style: normal;
}

.part-card.is-current {
  color: #fff;
  border-color: transparent;
  background: var(--ink);
}

.part-card.is-current span,
.part-card.is-current em {
  color: rgba(255, 255, 255, 0.78);
}

.primary-action,
.secondary-action {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 0 20px;
  border: 1px solid var(--ink);
  font-weight: 700;
}

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

.secondary-action {
  background: rgba(255, 250, 240, 0.75);
}

.hero-visual {
  position: relative;
  min-height: 520px;
  padding: 36px;
  border: 1px solid var(--line);
  background: rgba(255, 250, 240, 0.72);
  box-shadow: var(--shadow);
}

.workflow-board {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
  align-items: stretch;
  min-height: 444px;
}

.workflow-card {
  display: grid;
  grid-template-columns: 0.95fr 1.05fr;
  gap: 18px;
  align-items: center;
  padding: 18px;
  border: 2px solid var(--ink);
  background: #fbf6e9;
}

.workflow-label strong,
.workflow-label span {
  display: block;
}

.workflow-label strong {
  font-size: 22px;
}

.workflow-label span {
  margin-top: 6px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 700;
}

.workflow-card p {
  grid-column: 1 / -1;
  margin: 0;
  color: #425053;
  font-size: 14px;
  line-height: 1.65;
}

.workflow-arrow {
  width: 2px;
  height: 24px;
  justify-self: center;
  background: var(--coral);
}

.workflow-arrow::after {
  content: "";
  display: block;
  width: 12px;
  height: 12px;
  margin-top: 11px;
  margin-left: -5px;
  border-top: 2px solid var(--coral);
  border-right: 2px solid var(--coral);
  transform: rotate(135deg);
}

.cad-detail,
.sheet-detail,
.rule-detail {
  position: relative;
  min-height: 128px;
  overflow: hidden;
  border: 1px solid rgba(23, 33, 36, 0.28);
  background: rgba(255, 255, 255, 0.42);
}

.cad-detail {
  background:
    repeating-linear-gradient(135deg, rgba(214, 96, 69, 0.22) 0 7px, transparent 7px 14px),
    #fff7e8;
}

.cad-detail i {
  position: absolute;
  display: block;
}

.cad-detail .profile {
  inset: 38px 24px auto 20px;
  height: 78px;
  border: 3px solid var(--coral);
  border-left-width: 12px;
  background: rgba(255, 250, 240, 0.78);
}

.cad-detail .curve {
  width: 94px;
  height: 66px;
  right: 22px;
  bottom: 38px;
  border: 3px solid var(--teal);
  border-left: 0;
  border-bottom: 0;
  border-radius: 0 72px 0 0;
}

.cad-detail .joint {
  width: 92px;
  height: 3px;
  left: 32px;
  bottom: 58px;
  background: var(--ink);
  transform: rotate(-22deg);
}

.sheet-detail {
  padding: 26px 20px;
  background:
    linear-gradient(90deg, transparent 49%, rgba(31, 125, 120, 0.16) 50%, transparent 51%),
    #fffaf0;
}

.sheet-detail span {
  display: block;
  height: 24px;
  margin-bottom: 16px;
  border-left: 5px solid var(--teal);
  background: rgba(31, 125, 120, 0.12);
}

.sheet-detail span:nth-child(2) {
  width: 76%;
  border-left-color: var(--coral);
  background: rgba(214, 96, 69, 0.13);
}

.sheet-detail span:nth-child(3) {
  width: 62%;
}

.sheet-detail b {
  position: absolute;
  right: 18px;
  bottom: 18px;
  width: 78px;
  height: 78px;
  border: 2px solid var(--ink);
  background: repeating-linear-gradient(135deg, rgba(23, 33, 36, 0.14) 0 5px, transparent 5px 10px);
}

.rule-detail {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-auto-rows: 1fr;
  background: #edf5f2;
}

.rule-detail span {
  border-right: 1px solid rgba(31, 125, 120, 0.46);
  border-bottom: 1px solid rgba(31, 125, 120, 0.46);
  background: rgba(31, 125, 120, 0.08);
}

.rule-detail span:nth-child(3n) {
  background: rgba(181, 138, 59, 0.2);
}

.intro-grid,
.cad-layout {
  display: grid;
  grid-template-columns: 0.92fr 1.08fr;
  gap: 54px;
}

.section-title h2 {
  margin-bottom: 0;
}

.section-title.compact {
  margin-bottom: 28px;
}

.intro-copy {
  color: #3f4b4e;
  font-size: 17px;
  line-height: 1.9;
}

.pain-section,
.plugin-section,
.deliver-section {
  border-top: 1px solid var(--line);
}

.two-track,
.plugin-grid,
.metrics-grid,
.deliver-grid {
  display: grid;
  gap: 18px;
}

.two-track {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.track-card,
.solution-card,
.metric-card,
.deliver-grid article {
  padding: 28px;
  border: 1px solid var(--line);
  background: rgba(255, 250, 240, 0.8);
}

.track-card {
  position: relative;
  min-height: 310px;
}

.track-no {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  margin-bottom: 24px;
  color: #fff;
  background: var(--teal);
  font-weight: 800;
}

.track-card p,
.solution-card p,
.deliver-grid p {
  color: var(--muted);
  line-height: 1.75;
}

ul {
  margin: 20px 0 0;
  padding-left: 18px;
  color: #415052;
  line-height: 1.85;
}

.cad-section {
  border-top: 1px solid var(--line);
}

.cad-diagram {
  display: grid;
  grid-template-columns: 1fr;
  align-content: center;
  min-height: 470px;
  padding: 28px;
  border: 1px solid var(--ink);
  background: #202b2d;
  color: #fff;
}

.flow-node {
  padding: 18px 20px;
  border: 1px solid rgba(255, 255, 255, 0.22);
  background: rgba(255, 255, 255, 0.08);
  font-weight: 700;
}

.flow-node.strong {
  background: rgba(31, 125, 120, 0.95);
}

.flow-line {
  width: 2px;
  height: 28px;
  margin-left: 24px;
  background: var(--gold);
}

.cad-copy {
  align-self: center;
}

.cad-copy p {
  color: #3f4b4e;
  font-size: 17px;
  line-height: 1.85;
}

.ratio-strip {
  display: grid;
  grid-template-columns: 4fr 1fr;
  margin-top: 30px;
  border: 1px solid var(--ink);
}

.ratio-strip span {
  min-height: 58px;
  padding: 18px;
  color: #fff;
  font-weight: 800;
}

.ratio-strip span:first-child {
  background: var(--teal);
}

.ratio-strip span:last-child {
  background: var(--coral);
}

.plugin-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
  margin-top: 36px;
}

.ai-card {
  color: #fff;
  background: var(--ink);
  border-color: var(--ink);
}

.ai-card p {
  color: rgba(255, 255, 255, 0.78);
}

.pipeline {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 1px;
  margin-top: 22px;
  border: 1px solid var(--line);
  background: var(--line);
}

.pipeline div {
  min-height: 144px;
  padding: 22px;
  background: #fffaf0;
  color: #344346;
  font-weight: 700;
}

.pipeline span {
  display: block;
  margin-bottom: 26px;
  color: var(--coral);
  font-size: 28px;
}

.metrics-section {
  border-top: 1px solid var(--line);
}

.metrics-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
  margin-top: 36px;
}

.metric-card {
  min-height: 210px;
}

.metric-card.highlight {
  color: #fff;
  background: var(--teal-dark);
}

.metric-card.highlight p {
  color: rgba(255, 255, 255, 0.82);
}

.metric-value {
  display: block;
  margin-bottom: 28px;
  font-size: clamp(32px, 4vw, 52px);
  font-weight: 900;
  line-height: 1;
}

.metric-card p {
  color: var(--muted);
  line-height: 1.75;
}

.comparison-table {
  margin-top: 34px;
  border: 1px solid var(--line);
  background: rgba(255, 250, 240, 0.76);
}

.table-row {
  display: grid;
  grid-template-columns: 0.8fr 1fr 1.25fr 1fr;
  gap: 1px;
  border-top: 1px solid var(--line);
}

.table-row:first-child {
  border-top: 0;
}

.table-row span {
  padding: 18px;
  line-height: 1.6;
}

.table-row.header {
  color: #fff;
  background: var(--ink);
  font-weight: 800;
}

.deliver-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
  margin-top: 34px;
}

.footer {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  padding: 32px 5vw;
  color: var(--muted);
  border-top: 1px solid var(--line);
  background: rgba(255, 250, 240, 0.86);
}

@media (max-width: 980px) {
  .nav {
    display: none;
  }

  .hero,
  .intro-grid,
  .cad-layout {
    grid-template-columns: 1fr;
  }

  .hero {
    min-height: auto;
  }

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

  .workflow-board {
    grid-template-columns: 1fr;
    gap: 14px;
    min-height: 0;
  }

  .workflow-arrow {
    width: 2px;
    height: 34px;
    justify-self: center;
  }

  .workflow-arrow::after {
    margin-top: 11px;
    margin-left: -5px;
    transform: rotate(135deg);
  }

  .plugin-grid,
  .metrics-grid,
  .deliver-grid,
  .two-track {
    grid-template-columns: 1fr;
  }

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

  .comparison-table {
    border: 0;
    background: transparent;
  }

  .table-row.header {
    display: none;
  }

  .table-row {
    display: block;
    margin-top: 14px;
    border: 1px solid var(--line);
    background: rgba(255, 250, 240, 0.88);
  }

  .table-row:first-child {
    margin-top: 0;
  }

  .table-row span {
    display: grid;
    grid-template-columns: 9.5em minmax(0, 1fr);
    gap: 14px;
    align-items: start;
    padding: 14px 16px;
    border-top: 1px solid rgba(216, 208, 191, 0.72);
  }

  .table-row span:first-child {
    border-top: 0;
    background: rgba(31, 125, 120, 0.08);
    font-weight: 800;
  }

  .table-row span::before {
    content: attr(data-label);
    color: var(--teal-dark);
    font-size: 13px;
    font-weight: 800;
    line-height: 1.6;
  }
}

@media (max-width: 620px) {
  .section-shell {
    width: min(100% - 32px, 1180px);
    padding: 58px 0;
  }

  .topbar {
    padding: 0 16px;
  }

  .brand {
    font-size: 14px;
  }

  .hero-actions {
    flex-direction: column;
  }

  .primary-action,
  .secondary-action {
    width: 100%;
  }

  .part-switch {
    grid-template-columns: 1fr;
  }

  .part-card {
    min-height: 108px;
  }

  .hero-visual {
    padding: 18px;
  }

  .workflow-card {
    grid-template-columns: 1fr;
  }

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

  .footer {
    flex-direction: column;
  }

  .table-row span {
    grid-template-columns: 1fr;
    gap: 6px;
  }
}

.part2-nav,
.footer-part-link {
  color: var(--ink);
  font-weight: 800;
}

.part2-action {
  border-color: var(--coral);
  color: var(--ink);
  font-weight: 800;
}

.footer-part-link {
  color: var(--coral);
  text-decoration: none;
}
/* ===== Part 1 Bridge Tone: closer to Part 2 chrome ===== */
:root {
  --navy: #0f2742;
  --blue: #1f6f9f;
  --aqua: #4bb6b7;
  --gold: #c7953c;
}

body {
  background:
    radial-gradient(circle at 8% 8%, rgba(75, 182, 183, 0.12), transparent 30rem),
    radial-gradient(circle at 92% 20%, rgba(199, 149, 60, 0.11), transparent 28rem),
    var(--paper);
}

.primary-action {
  border-color: var(--navy);
  background: linear-gradient(135deg, var(--navy), var(--blue));
}

.secondary-action {
  border-color: rgba(31, 111, 159, 0.28);
  color: var(--navy);
  background: rgba(255, 255, 255, 0.74);
}

.part-card {
  border-color: rgba(31, 111, 159, 0.16);
  border-radius: 22px;
  background: rgba(255, 255, 255, 0.74);
}

.part-card span {
  color: var(--blue);
}

.part-card.is-current {
  background:
    radial-gradient(circle at 88% 20%, rgba(255, 255, 255, 0.2), transparent 7rem),
    linear-gradient(135deg, var(--navy), var(--blue));
}