:root {
  --ink: #172832;
  --muted: #5e7078;
  --paper: #f5faf8;
  --white: #ffffff;
  --sky: #1596b8;
  --sky-dark: #0d6f89;
  --leaf: #78c85a;
  --coral: #ff6f61;
  --line: #d8e7e4;
  --shadow: 0 14px 36px rgba(24, 55, 65, 0.12);
  --container: 1160px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: "Microsoft YaHei", "PingFang SC", Arial, sans-serif;
  line-height: 1.75;
}

body::before {
  position: fixed;
  inset: 0;
  z-index: -1;
  background-image: linear-gradient(rgba(21, 150, 184, 0.045) 1px, transparent 1px), linear-gradient(90deg, rgba(21, 150, 184, 0.045) 1px, transparent 1px);
  background-size: 32px 32px;
  content: "";
}

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

a {
  color: var(--sky-dark);
  text-decoration: none;
}

a:hover {
  color: var(--coral);
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

.container {
  width: min(calc(100% - 40px), var(--container));
  margin-inline: auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  border-bottom: 1px solid rgba(216, 231, 228, 0.9);
  background: rgba(255, 255, 255, 0.94);
  backdrop-filter: blur(12px);
}

.nav-wrap {
  display: flex;
  min-height: 72px;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  flex: 0 0 auto;
  gap: 10px;
  color: var(--ink);
  font-size: 20px;
  font-weight: 800;
}

.brand img {
  width: 42px;
  height: 42px;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 28px;
}

.main-nav > a:not(.download-btn) {
  position: relative;
  color: var(--ink);
  font-size: 15px;
  font-weight: 700;
}

.main-nav > a[aria-current="page"]::after {
  position: absolute;
  right: 0;
  bottom: -8px;
  left: 0;
  height: 3px;
  background: var(--leaf);
  content: "";
}

.nav-toggle {
  display: none;
  width: 42px;
  height: 42px;
  padding: 9px;
  border: 0;
  background: transparent;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  height: 2px;
  margin: 5px 0;
  background: var(--ink);
}

.download-btn {
  display: inline-flex;
  min-height: 46px;
  align-items: center;
  justify-content: center;
  padding: 10px 24px;
  border: 2px solid var(--ink);
  border-radius: 6px;
  color: var(--white);
  background: var(--ink);
  box-shadow: 5px 5px 0 var(--leaf);
  font-weight: 800;
  transition: transform 180ms ease, box-shadow 180ms ease;
}

.download-btn:hover {
  color: var(--white);
  box-shadow: 2px 2px 0 var(--leaf);
  transform: translate(3px, 3px);
}

.download-btn.light {
  border-color: var(--white);
  color: var(--ink);
  background: var(--white);
  box-shadow: 5px 5px 0 var(--coral);
}

.hero {
  position: relative;
  overflow: hidden;
  padding: 66px 0 54px;
  background: var(--white);
}

.hero::after {
  position: absolute;
  top: 92px;
  right: -40px;
  width: 38%;
  height: 180px;
  border-top: 18px solid var(--leaf);
  border-bottom: 8px solid var(--coral);
  transform: skewY(-8deg);
  content: "";
  opacity: 0.3;
}

.hero-grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(300px, 0.9fr);
  align-items: center;
  gap: 54px;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 14px;
  color: var(--sky-dark);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0;
}

.eyebrow::before {
  width: 28px;
  height: 4px;
  background: var(--coral);
  content: "";
}

h1,
h2,
h3 {
  margin-top: 0;
  line-height: 1.25;
  letter-spacing: 0;
}

h1 {
  max-width: 620px;
  margin-bottom: 20px;
  font-size: clamp(40px, 6vw, 72px);
}

h2 {
  margin-bottom: 30px;
  font-size: clamp(28px, 4vw, 42px);
}

h3 {
  margin-bottom: 12px;
  font-size: 20px;
}

.hero-copy > p:not(.eyebrow) {
  max-width: 640px;
  margin: 0 0 26px;
  color: var(--muted);
  font-size: 18px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 18px;
}

.text-link {
  border-bottom: 2px solid var(--sky);
  color: var(--ink);
  font-weight: 800;
}

.version-line {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 22px;
  margin: 24px 0 0;
  padding: 0;
  color: var(--muted);
  font-size: 14px;
  list-style: none;
}

.phone-stage {
  position: relative;
  display: grid;
  min-height: 540px;
  place-items: center;
}

.phone-stage::before {
  position: absolute;
  width: 330px;
  height: 430px;
  border: 4px solid var(--ink);
  background: var(--sky);
  box-shadow: 22px 22px 0 var(--leaf);
  content: "";
  transform: rotate(5deg);
}

.app-shot {
  width: auto;
  max-width: 400px;
  height: auto;
}

.phone-stage .app-shot {
  position: relative;
  z-index: 1;
  max-height: 500px;
  border: 8px solid var(--ink);
  border-radius: 26px;
  box-shadow: var(--shadow);
}

.metric-strip {
  background: var(--ink);
  color: var(--white);
}

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

.metric {
  min-height: 116px;
  padding: 24px;
  border-right: 1px solid rgba(255, 255, 255, 0.16);
}

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

.metric strong {
  display: block;
  color: var(--leaf);
  font-size: 25px;
}

.metric span {
  color: #c7d9dd;
  font-size: 14px;
}

.section {
  padding: 86px 0;
}

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

.section-dark {
  color: var(--white);
  background: var(--ink);
}

.section-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 30px;
}

.section-heading .text-link {
  margin-bottom: 35px;
  color: inherit;
}

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

.feature-item {
  min-height: 190px;
  padding: 30px;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: var(--white);
}

.feature-number {
  display: block;
  margin-bottom: 30px;
  color: var(--coral);
  font-size: 13px;
  font-weight: 900;
}

.feature-item p,
.path-card p,
.review blockquote,
.article-body p,
.article-body li {
  color: var(--muted);
}

.feature-item p,
.path-card p {
  margin-bottom: 0;
}

.shots-track {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 28px;
}

.shot-card {
  margin: 0;
  padding: 28px 20px 20px;
  border: 1px solid #314650;
  border-radius: 6px;
  background: #213640;
  text-align: center;
}

.shot-card .app-shot {
  margin: 0 auto;
}

.shot-card figcaption {
  padding-top: 18px;
  color: #d3e1e4;
  font-size: 14px;
}

.paths {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 24px;
}

.path-card {
  position: relative;
  min-height: 270px;
  overflow: hidden;
  padding: 38px;
  border: 2px solid var(--ink);
  border-radius: 6px;
  background: var(--white);
}

.path-card:first-child {
  background: #e6f7ee;
}

.path-card:last-child {
  background: #fff1ed;
}

.path-card::after {
  position: absolute;
  right: -38px;
  bottom: -38px;
  width: 140px;
  height: 140px;
  border: 20px solid rgba(21, 150, 184, 0.15);
  border-radius: 50%;
  content: "";
}

.path-card .text-link {
  display: inline-block;
  margin-top: 22px;
}

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

.review {
  padding: 28px;
  border-left: 5px solid var(--sky);
  background: var(--white);
}

.review:nth-child(2) {
  border-left-color: var(--leaf);
}

.review:nth-child(3) {
  border-left-color: var(--coral);
}

.review blockquote {
  min-height: 112px;
  margin: 0 0 18px;
}

.review cite {
  font-size: 14px;
  font-style: normal;
  font-weight: 800;
}

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

.faq-mini {
  padding: 26px;
  border-top: 5px solid var(--leaf);
  background: var(--white);
}

.faq-mini p {
  margin: 0;
  color: var(--muted);
}

.download-band {
  position: relative;
  overflow: hidden;
  padding: 64px 0;
  color: var(--white);
  background: var(--sky-dark);
}

.download-band::before {
  position: absolute;
  top: -40px;
  right: 6%;
  width: 260px;
  height: 30px;
  border-top: 10px solid var(--leaf);
  border-bottom: 6px solid var(--coral);
  transform: rotate(-10deg);
  content: "";
}

.download-band-inner {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 30px;
}

.download-band h2 {
  margin-bottom: 10px;
}

.download-band p {
  margin: 0;
  color: #d5eef4;
}

.band-note {
  color: #d5eef4;
}

.site-footer {
  padding: 42px 0 26px;
  color: #bdd0d5;
  background: #10212a;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 36px;
}

.footer-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
}

.footer-nav a {
  color: var(--white);
}

.disclaimer {
  max-width: 780px;
  margin: 18px 0 0;
  font-size: 13px;
}

.copyright {
  margin: 22px 0 0;
  padding-top: 22px;
  border-top: 1px solid #28404a;
  font-size: 13px;
}

.page-hero {
  padding: 70px 0 48px;
  color: var(--white);
  background: var(--ink);
}

.page-hero h1 {
  margin-bottom: 18px;
  font-size: clamp(36px, 5vw, 58px);
}

.page-hero p:not(.eyebrow) {
  max-width: 720px;
  margin: 0;
  color: #c8d8dc;
  font-size: 17px;
}

.page-hero .eyebrow {
  color: var(--leaf);
}

.article-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 280px;
  align-items: start;
  gap: 46px;
}

.article-body section {
  margin-bottom: 58px;
  scroll-margin-top: 100px;
}

.article-body h2 {
  margin-bottom: 24px;
  padding-bottom: 14px;
  border-bottom: 4px solid var(--leaf);
  font-size: 30px;
}

.article-body h3 {
  margin-top: 28px;
}

.article-body a:not(.download-btn) {
  border-bottom: 1px solid currentColor;
  font-weight: 700;
}

.article-body figure {
  margin: 28px 0;
  padding: 20px;
  border: 1px solid var(--line);
  background: var(--white);
}

.article-body figure .app-shot {
  margin: 0 auto;
}

.article-body figcaption {
  padding-top: 15px;
  color: var(--muted);
  text-align: center;
  font-size: 13px;
}

.step-list {
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: steps;
}

.step-list li {
  position: relative;
  min-height: 88px;
  margin-bottom: 18px;
  padding: 22px 24px 22px 76px;
  border: 1px solid var(--line);
  background: var(--white);
  counter-increment: steps;
}

.step-list li::before {
  position: absolute;
  top: 20px;
  left: 20px;
  display: grid;
  width: 38px;
  height: 38px;
  place-items: center;
  color: var(--white);
  background: var(--sky);
  content: counter(steps, decimal-leading-zero);
  font-weight: 900;
}

.step-list strong {
  display: block;
  margin-bottom: 5px;
  color: var(--ink);
}

.callout {
  margin: 26px 0;
  padding: 22px 26px;
  border-left: 6px solid var(--coral);
  background: #fff1ed;
}

.callout p {
  margin: 0;
  color: #734039;
}

.side-nav {
  position: sticky;
  top: 96px;
  padding: 24px;
  border: 1px solid var(--line);
  background: var(--white);
}

.side-nav strong {
  display: block;
  margin-bottom: 14px;
}

.side-nav a {
  display: block;
  padding: 8px 0;
  border-bottom: 1px solid var(--line);
  color: var(--muted);
  font-size: 14px;
}

.side-nav .download-btn {
  margin-top: 20px;
  color: var(--white);
}

.function-row {
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 22px;
  padding: 26px 0;
  border-bottom: 1px solid var(--line);
}

.function-row h3 {
  color: var(--sky-dark);
}

.function-row p {
  margin: 0;
}

.faq-list {
  border-top: 1px solid var(--line);
}

.faq-item {
  border-bottom: 1px solid var(--line);
}

.faq-question {
  display: flex;
  width: 100%;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 22px 4px;
  border: 0;
  color: var(--ink);
  background: transparent;
  cursor: pointer;
  text-align: left;
  font-family: inherit;
  font-size: 18px;
  font-weight: 800;
}

.faq-question::after {
  flex: 0 0 auto;
  color: var(--sky);
  content: "+";
  font-size: 28px;
}

.faq-item.open .faq-question::after {
  content: "−";
}

.faq-answer {
  display: none;
  padding: 0 44px 22px 4px;
}

.faq-answer p {
  margin: 0;
}

.faq-item.open .faq-answer {
  display: block;
}

.reveal {
  opacity: 1;
  transform: none;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

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

  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
}

@media (max-width: 900px) {
  .nav-toggle {
    display: block;
  }

  .main-nav {
    position: absolute;
    top: 72px;
    right: 0;
    left: 0;
    display: none;
    padding: 22px 20px 28px;
    border-bottom: 1px solid var(--line);
    background: var(--white);
  }

  .main-nav.open {
    display: grid;
  }

  .main-nav > a[aria-current="page"]::after {
    display: none;
  }

  .hero-grid,
  .paths,
  .article-layout {
    grid-template-columns: 1fr;
  }

  .hero-copy {
    text-align: center;
  }

  .hero-copy > p:not(.eyebrow),
  .hero-copy h1 {
    margin-inline: auto;
  }

  .eyebrow,
  .hero-actions,
  .version-line {
    justify-content: center;
  }

  .phone-stage {
    min-height: 500px;
  }

  .metrics,
  .shots-track,
  .review-grid,
  .faq-preview {
    grid-template-columns: repeat(2, 1fr);
  }

  .shots-track .shot-card:last-child,
  .review-grid .review:last-child,
  .faq-preview .faq-mini:last-child {
    grid-column: 1 / -1;
  }

  .side-nav {
    position: static;
    order: -1;
  }
}

@media (max-width: 640px) {
  .container {
    width: min(calc(100% - 28px), var(--container));
  }

  .hero {
    padding-top: 46px;
  }

  h1 {
    font-size: 40px;
  }

  h2 {
    font-size: 30px;
  }

  .phone-stage::before {
    width: 190px;
    height: 250px;
  }

  .hero-grid {
    gap: 20px;
  }

  .phone-stage {
    min-height: 310px;
  }

  .phone-stage .app-shot {
    max-height: 300px;
  }

  .metrics,
  .feature-grid,
  .shots-track,
  .review-grid,
  .faq-preview {
    grid-template-columns: 1fr;
  }

  .metric {
    min-height: auto;
    border-right: 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.16);
  }

  .shots-track .shot-card:last-child,
  .review-grid .review:last-child,
  .faq-preview .faq-mini:last-child {
    grid-column: auto;
  }

  .section {
    padding: 64px 0;
  }

  .section-heading,
  .download-band-inner,
  .footer-grid {
    align-items: flex-start;
    flex-direction: column;
  }

  .section-heading,
  .download-band-inner {
    display: flex;
  }

  .footer-grid {
    display: grid;
    grid-template-columns: 1fr;
  }

  .section-heading .text-link {
    margin-top: -14px;
    margin-bottom: 28px;
  }

  .function-row {
    grid-template-columns: 1fr;
    gap: 4px;
  }

  .path-card {
    padding: 28px;
  }
}