:root {
  color-scheme: light;
  --ink: #171a1c;
  --muted: #5f686c;
  --paper: #f7f8f4;
  --white: #ffffff;
  --line: #d8ddda;
  --blue: #225aa5;
  --green: #2c7a58;
  --coral: #c94f40;
  --yellow: #d69b24;
  --charcoal: #202629;
  --soft-green: #e7f1eb;
  --soft-blue: #e8eff8;
  --soft-coral: #f8eae7;
  --shadow: 0 16px 44px rgba(21, 27, 29, 0.11);
  font-family:
    "Segoe UI",
    "Microsoft YaHei UI",
    "Microsoft YaHei",
    Arial,
    sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  line-height: 1.65;
}

button,
a {
  font: inherit;
}

button {
  color: inherit;
}

a {
  color: inherit;
}

.site-header {
  position: absolute;
  z-index: 10;
  top: 0;
  left: 0;
  right: 0;
  height: 70px;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  padding: 0 5vw;
  color: #fff;
  border-bottom: 1px solid rgba(255, 255, 255, 0.28);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  width: max-content;
  font-weight: 700;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border: 1px solid rgba(255, 255, 255, 0.82);
  border-radius: 6px;
  font-size: 12px;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 30px;
}

.site-nav a {
  color: rgba(255, 255, 255, 0.84);
  text-decoration: none;
  font-size: 14px;
}

.site-nav a:hover,
.site-nav a:focus-visible {
  color: #fff;
}

.header-status {
  justify-self: end;
  font-size: 13px;
  color: rgba(255, 255, 255, 0.78);
}

.hero {
  position: relative;
  min-height: 640px;
  height: min(760px, 82svh);
  overflow: hidden;
  color: #fff;
  background: #2b302e;
}

.hero-image,
.hero-shade {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.hero-image {
  object-fit: cover;
  object-position: center;
}

.hero-shade {
  background: rgba(13, 18, 19, 0.61);
}

.hero-content {
  position: relative;
  z-index: 2;
  display: flex;
  flex-direction: column;
  justify-content: center;
  width: min(760px, 86vw);
  height: 100%;
  margin-left: 8vw;
  padding-top: 54px;
}

.eyebrow,
.section-kicker {
  margin: 0 0 12px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0;
  text-transform: uppercase;
}

.eyebrow {
  color: #f0c557;
}

.hero h1 {
  max-width: 760px;
  margin: 0;
  font-size: 68px;
  line-height: 1.08;
  letter-spacing: 0;
}

.hero-lead {
  max-width: 700px;
  margin: 24px 0 0;
  color: rgba(255, 255, 255, 0.9);
  font-size: 21px;
  line-height: 1.65;
}

.hero-actions {
  display: flex;
  align-items: center;
  gap: 28px;
  margin-top: 34px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 0 20px;
  border-radius: 6px;
  text-decoration: none;
  font-weight: 700;
}

.button-primary {
  color: #17211b;
  background: #f5c958;
}

.button-primary:hover,
.button-primary:focus-visible {
  background: #ffda78;
}

.text-link {
  color: #fff;
  text-underline-offset: 6px;
}

.hero-proof {
  position: absolute;
  z-index: 2;
  right: 5vw;
  bottom: 28px;
  display: flex;
  gap: 20px;
  color: rgba(255, 255, 255, 0.78);
  font-size: 13px;
}

.hero-proof span + span::before {
  content: "/";
  margin-right: 20px;
  color: rgba(255, 255, 255, 0.4);
}

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

.intro-band {
  padding: 72px 0;
  background: var(--white);
  border-bottom: 1px solid var(--line);
}

.intro-layout {
  display: grid;
  grid-template-columns: minmax(280px, 0.9fr) minmax(400px, 1.25fr);
  gap: 80px;
  align-items: start;
}

.section-kicker {
  color: var(--coral);
}

h2 {
  margin: 0;
  font-size: 40px;
  line-height: 1.2;
  letter-spacing: 0;
}

.intro-copy {
  margin: 6px 0 0;
  color: #3f484c;
  font-size: 20px;
}

.architecture-section,
.quality-section,
.evidence-section {
  padding: 108px 0;
}

.section-heading {
  max-width: 780px;
  margin-bottom: 46px;
}

.section-heading.compact {
  margin-bottom: 36px;
}

.section-heading > p:last-child {
  margin: 18px 0 0;
  color: var(--muted);
  font-size: 17px;
}

.workflow-tool {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: var(--shadow);
  overflow: hidden;
}

.workflow-tabs {
  display: grid;
  grid-template-columns: repeat(7, minmax(98px, 1fr));
  overflow-x: auto;
  border-bottom: 1px solid var(--line);
}

.workflow-tab {
  min-height: 82px;
  padding: 12px 8px;
  border: 0;
  border-right: 1px solid var(--line);
  background: #f2f4f1;
  cursor: pointer;
  font-weight: 700;
}

.workflow-tab:last-child {
  border-right: 0;
}

.workflow-tab span {
  display: block;
  margin-bottom: 4px;
  color: var(--muted);
  font-size: 12px;
}

.workflow-tab:hover,
.workflow-tab:focus-visible {
  background: #e9eeea;
}

.workflow-tab.is-active {
  color: #fff;
  background: var(--charcoal);
}

.workflow-tab.is-active span {
  color: #f5c958;
}

.stage-panel {
  min-height: 280px;
  display: grid;
  grid-template-columns: 120px minmax(300px, 1.2fr) minmax(300px, 1fr);
  gap: 34px;
  align-items: center;
  padding: 46px 50px;
}

.stage-panel.is-changing {
  opacity: 0.45;
}

.stage-index {
  display: grid;
  place-items: center;
  width: 96px;
  height: 96px;
  border: 2px solid var(--blue);
  border-radius: 50%;
  color: var(--blue);
  font-size: 30px;
  font-weight: 800;
}

.stage-label {
  margin: 0 0 6px;
  color: var(--blue);
  font-size: 13px;
  font-weight: 700;
}

.stage-copy h3 {
  margin: 0;
  font-size: 28px;
  line-height: 1.3;
}

.stage-copy p:last-child {
  margin: 16px 0 0;
  color: var(--muted);
}

.stage-facts {
  margin: 0;
}

.stage-facts div {
  padding: 18px 0;
  border-top: 1px solid var(--line);
}

.stage-facts div:last-child {
  border-bottom: 1px solid var(--line);
}

.stage-facts dt {
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
}

.stage-facts dd {
  margin: 5px 0 0;
  font-weight: 650;
}

.collaboration-band {
  padding: 94px 0 100px;
  color: #f7f8f4;
  background: var(--charcoal);
}

.collaboration-band .section-heading > p:last-child {
  color: #b9c1c0;
}

.role-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

.role-card {
  min-height: 250px;
  padding: 26px;
  border: 1px solid #434b4d;
  border-top: 5px solid var(--blue);
  border-radius: 6px;
  background: #2a3032;
}

.role-card.role-worker {
  border-top-color: var(--green);
}

.role-card.role-gpt {
  border-top-color: var(--yellow);
}

.role-card.role-human {
  border-top-color: var(--coral);
}

.role-number {
  margin: 0 0 28px;
  color: #9fa8a8;
  font-size: 12px;
}

.role-card h3 {
  margin: 0;
  font-size: 20px;
}

.role-card p:last-child {
  margin: 14px 0 0;
  color: #c5cccb;
  font-size: 14px;
}

.quality-section {
  background: var(--white);
}

.quality-header {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 30px;
  margin-bottom: 46px;
}

.mode-switch {
  display: grid;
  grid-template-columns: 1fr 1fr;
  width: 260px;
  padding: 4px;
  border: 1px solid var(--line);
  border-radius: 7px;
  background: #eef0ed;
}

.mode-button {
  min-height: 40px;
  border: 0;
  border-radius: 5px;
  background: transparent;
  cursor: pointer;
  font-size: 14px;
  font-weight: 700;
}

.mode-button.is-active {
  color: #fff;
  background: var(--charcoal);
}

.quality-comparison {
  display: grid;
  grid-template-columns: minmax(300px, 0.85fr) minmax(450px, 1.2fr);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.quality-summary {
  padding: 52px 60px 52px 0;
  border-right: 1px solid var(--line);
}

.summary-label {
  margin: 0 0 12px;
  color: var(--green);
  font-size: 13px;
  font-weight: 700;
}

.quality-summary h3 {
  margin: 0;
  font-size: 30px;
  line-height: 1.35;
}

.quality-summary p:last-child {
  margin: 18px 0 0;
  color: var(--muted);
}

.quality-bars {
  display: grid;
  gap: 26px;
  padding: 50px 0 50px 60px;
}

.quality-row {
  display: grid;
  grid-template-columns: 90px 1fr 76px;
  gap: 16px;
  align-items: center;
  font-size: 13px;
}

.quality-row > span {
  font-weight: 700;
}

.quality-row strong {
  color: var(--muted);
  font-size: 12px;
}

.quality-track {
  height: 9px;
  overflow: hidden;
  background: #e3e7e4;
}

.quality-track i {
  display: block;
  width: 88%;
  height: 100%;
  background: var(--green);
  transition: width 260ms ease, background-color 260ms ease;
}

.hybrid-band {
  padding: 108px 0;
  background: #edf1ec;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.hybrid-layout {
  display: grid;
  grid-template-columns: minmax(260px, 0.8fr) minmax(500px, 1.4fr);
  gap: 70px;
}

.hybrid-intro p:last-child {
  margin: 20px 0 0;
  color: var(--muted);
}

.hybrid-lanes {
  display: grid;
  grid-template-columns: 1fr 1fr;
  border: 1px solid var(--line);
  border-radius: 8px;
  overflow: hidden;
}

.lane {
  padding: 34px;
  background: var(--white);
}

.lane + .lane {
  border-left: 1px solid var(--line);
}

.lane-mark {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  color: #fff;
  background: var(--blue);
  font-weight: 800;
}

.lane-a .lane-mark {
  background: var(--coral);
}

.lane h3 {
  margin: 20px 0 0;
  font-size: 23px;
}

.lane p {
  margin: 10px 0 0;
  color: var(--muted);
}

.lane ul {
  margin: 22px 0 0;
  padding-left: 18px;
}

.lane li + li {
  margin-top: 8px;
}

.claim-diff {
  grid-column: 2;
  display: grid;
  grid-template-columns: auto 180px 1fr;
  gap: 20px;
  align-items: center;
  padding: 24px 28px;
  color: #fff;
  background: var(--charcoal);
  border-radius: 6px;
}

.claim-diff span {
  color: #b9c1c0;
  font-size: 12px;
}

.claim-diff strong {
  color: #f5c958;
}

.claim-diff p {
  margin: 0;
  color: #d5dad9;
  font-size: 13px;
}

.metric-strip {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  margin-bottom: 36px;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.metric-strip > div {
  min-height: 142px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 24px;
  border-right: 1px solid var(--line);
}

.metric-strip > div:last-child {
  border-right: 0;
}

.metric-strip strong {
  font-size: 32px;
  line-height: 1.2;
}

.metric-strip span {
  margin-top: 8px;
  color: var(--muted);
  font-size: 13px;
}

.evidence-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}

.evidence-card {
  padding: 28px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--white);
}

.evidence-tag {
  margin: 0;
  color: var(--blue);
  font-size: 12px;
  font-weight: 700;
}

.evidence-card h3 {
  margin: 14px 0 0;
  font-size: 21px;
  line-height: 1.4;
}

.evidence-card p:last-child {
  margin: 14px 0 0;
  color: var(--muted);
  font-size: 14px;
}

.method-note {
  margin-top: 24px;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.method-note summary {
  padding: 20px 0;
  cursor: pointer;
  font-weight: 700;
}

.method-note > div {
  max-width: 820px;
  padding: 0 0 22px;
  color: var(--muted);
}

.method-note p {
  margin: 0;
}

.method-note p + p {
  margin-top: 12px;
}

.tradeoff-band {
  padding: 82px 0;
  color: #fff;
  background: var(--coral);
}

.tradeoff-band .section-kicker {
  color: #ffe2a4;
}

.tradeoff-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 80px;
}

.tradeoff-list {
  border-top: 1px solid rgba(255, 255, 255, 0.42);
}

.tradeoff-list p {
  margin: 0;
  padding: 16px 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.42);
}

footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 30px;
  min-height: 110px;
  padding: 28px 5vw;
  color: #c7cdcb;
  background: #15191b;
}

footer div {
  display: flex;
  align-items: baseline;
  gap: 12px;
}

footer strong {
  color: #fff;
  font-size: 20px;
}

footer p,
footer span {
  margin: 0;
  font-size: 13px;
}

@media (max-width: 980px) {
  .site-header {
    grid-template-columns: 1fr auto;
  }

  .site-nav {
    display: none;
  }

  .header-status {
    grid-column: 2;
  }

  .hero {
    min-height: 620px;
    height: 80svh;
  }

  .hero h1 {
    font-size: 54px;
  }

  .hero-lead {
    font-size: 18px;
  }

  .hero-proof {
    left: 8vw;
    right: auto;
  }

  .intro-layout,
  .hybrid-layout,
  .tradeoff-layout {
    grid-template-columns: 1fr;
    gap: 36px;
  }

  .stage-panel {
    grid-template-columns: 90px 1fr;
  }

  .stage-index {
    width: 78px;
    height: 78px;
    font-size: 24px;
  }

  .stage-facts {
    grid-column: 1 / -1;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
  }

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

  .quality-comparison {
    grid-template-columns: 1fr;
  }

  .quality-summary {
    padding: 42px 0;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .quality-bars {
    padding: 42px 0;
  }

  .claim-diff {
    grid-column: 1;
  }

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

@media (max-width: 680px) {
  .site-header {
    height: 62px;
    padding: 0 20px;
  }

  .hero {
    min-height: 590px;
    height: 78svh;
    max-height: 680px;
  }

  .hero-image {
    object-position: 58% center;
  }

  .hero-content {
    width: auto;
    margin: 0 22px;
    padding-top: 42px;
  }

  .hero h1 {
    font-size: 42px;
  }

  .hero-lead {
    font-size: 17px;
  }

  .hero-actions {
    align-items: flex-start;
    flex-direction: column;
    gap: 18px;
  }

  .hero-proof {
    left: 22px;
    right: 22px;
    bottom: 18px;
    gap: 10px;
    overflow: hidden;
    white-space: nowrap;
  }

  .hero-proof span + span::before {
    margin-right: 10px;
  }

  .section-inner {
    width: min(100% - 40px, 1180px);
  }

  .intro-band {
    padding: 56px 0;
  }

  .intro-copy {
    font-size: 17px;
  }

  .architecture-section,
  .quality-section,
  .evidence-section,
  .hybrid-band {
    padding: 78px 0;
  }

  h2 {
    font-size: 32px;
  }

  .workflow-tabs {
    grid-template-columns: repeat(7, 92px);
  }

  .workflow-tab {
    min-height: 72px;
  }

  .stage-panel {
    grid-template-columns: 1fr;
    gap: 24px;
    padding: 30px 24px;
  }

  .stage-index {
    width: 62px;
    height: 62px;
    font-size: 20px;
  }

  .stage-copy h3 {
    font-size: 24px;
  }

  .stage-facts {
    grid-column: auto;
    grid-template-columns: 1fr;
    gap: 0;
  }

  .role-grid,
  .metric-strip {
    grid-template-columns: 1fr;
  }

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

  .quality-header {
    align-items: stretch;
    flex-direction: column;
  }

  .mode-switch {
    width: 100%;
  }

  .quality-summary h3 {
    font-size: 26px;
  }

  .quality-row {
    grid-template-columns: 78px 1fr;
  }

  .quality-row strong {
    grid-column: 2;
  }

  .hybrid-lanes {
    grid-template-columns: 1fr;
  }

  .lane + .lane {
    border-top: 1px solid var(--line);
    border-left: 0;
  }

  .claim-diff {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .metric-strip > div {
    min-height: 108px;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .metric-strip > div:last-child {
    border-bottom: 0;
  }

  footer {
    align-items: flex-start;
    flex-direction: column;
  }
}

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

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}