:root {
  --ink: #0b2330;
  --ink-soft: #36515b;
  --sky: #23a7c9;
  --sky-soft: #e4f6f9;
  --green: #43b77a;
  --yellow: #f6c453;
  --coral: #ef6b62;
  --paper: #f7fbfa;
  --white: #ffffff;
  --line: #dce9e6;
  --shadow: 0 16px 44px rgba(11, 35, 48, 0.12);
  --radius: 8px;
  --wrap: min(1160px, calc(100% - 40px));
}

* {
  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.menu-open {
  overflow: hidden;
}

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

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

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

.skip-link {
  position: fixed;
  top: 8px;
  left: 8px;
  z-index: 999;
  padding: 10px 14px;
  color: var(--white);
  background: var(--ink);
  transform: translateY(-150%);
}

.skip-link:focus {
  transform: translateY(0);
}

.container {
  width: var(--wrap);
  margin-inline: auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 1px solid rgba(220, 233, 230, 0.9);
  background: rgba(247, 251, 250, 0.94);
  backdrop-filter: blur(16px);
}

.nav-shell {
  display: flex;
  min-height: 72px;
  align-items: center;
  gap: 32px;
}

.brand {
  display: inline-flex;
  flex-shrink: 0;
  align-items: center;
  gap: 10px;
  font-size: 19px;
  font-weight: 800;
}

.brand img {
  width: 42px;
  height: 42px;
  border-radius: 8px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
  margin-left: auto;
}

.nav-links a:not(.button) {
  color: var(--ink-soft);
  font-size: 15px;
  font-weight: 700;
}

.nav-links a[aria-current="page"],
.nav-links a:not(.button):hover {
  color: var(--sky);
}

.button {
  display: inline-flex;
  min-height: 46px;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 20px;
  border: 1px solid var(--ink);
  border-radius: 6px;
  color: var(--white);
  background: var(--ink);
  font-size: 15px;
  font-weight: 800;
  cursor: pointer;
  transition: transform 180ms ease, background 180ms ease;
}

.button:hover {
  background: #173d4c;
  transform: translateY(-2px);
}

.button.accent {
  border-color: var(--sky);
  background: var(--sky);
}

.button.ghost {
  color: var(--ink);
  border-color: var(--line);
  background: var(--white);
}

.menu-toggle {
  display: none;
  width: 44px;
  height: 44px;
  margin-left: auto;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--white);
  cursor: pointer;
}

.menu-toggle span,
.menu-toggle::before,
.menu-toggle::after {
  display: block;
  width: 20px;
  height: 2px;
  margin: 5px auto;
  background: var(--ink);
  content: "";
}

.menu-toggle .menu-glyph {
  display: inline;
  width: auto;
  height: auto;
  margin: 0;
  color: var(--ink);
  background: none;
  font-size: 24px;
  line-height: 1;
}

.menu-toggle::before,
.menu-toggle::after {
  display: none;
}

.hero {
  position: relative;
  overflow: hidden;
  padding: 74px 0 54px;
  background: var(--white);
}

.hero::before {
  position: absolute;
  top: 0;
  right: 0;
  width: 42%;
  height: 100%;
  background: var(--sky-soft);
  content: "";
}

.hero-grid {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(320px, 0.95fr);
  align-items: center;
  gap: 72px;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 16px;
  color: #1687a3;
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0;
}

.eyebrow::before {
  width: 22px;
  height: 3px;
  background: var(--yellow);
  content: "";
}

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

h1 {
  max-width: 660px;
  margin-bottom: 22px;
  font-size: clamp(38px, 6vw, 68px);
}

h2 {
  margin-bottom: 28px;
  font-size: clamp(27px, 4vw, 40px);
}

h3 {
  margin-bottom: 10px;
  font-size: 19px;
}

.hero-copy > p:not(.eyebrow) {
  max-width: 620px;
  margin: 0 0 26px;
  color: var(--ink-soft);
  font-size: 18px;
}

.hero-actions,
.cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.trust-row {
  display: flex;
  flex-wrap: wrap;
  gap: 16px 28px;
  margin-top: 32px;
  padding: 0;
  color: var(--ink-soft);
  list-style: none;
}

.trust-row strong {
  display: block;
  color: var(--ink);
  font-size: 18px;
}

.hero-visual {
  position: relative;
  min-height: 520px;
}

.phone-card {
  position: absolute;
  width: min(270px, 70%);
  padding: 9px;
  border: 1px solid rgba(11, 35, 48, 0.12);
  border-radius: 34px;
  background: var(--white);
  box-shadow: var(--shadow);
}

.phone-card img {
  width: 100%;
  max-width: 400px;
  border-radius: 27px;
}

.phone-card.primary {
  top: 0;
  right: 10%;
  z-index: 2;
}

.phone-card.secondary {
  bottom: -32px;
  left: 2%;
  width: min(218px, 58%);
  transform: rotate(-4deg);
}

.section {
  padding: 86px 0;
}

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

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

.section-label {
  margin: 0 0 10px;
  color: var(--sky);
  font-size: 13px;
  font-weight: 800;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
}

.feature-item {
  min-height: 238px;
  padding: 26px;
  border-top: 4px solid var(--sky);
  background: var(--white);
}

.feature-item:nth-child(2) {
  border-color: var(--green);
}

.feature-item:nth-child(3) {
  border-color: var(--yellow);
}

.feature-item:nth-child(4) {
  border-color: var(--coral);
}

.feature-index {
  display: inline-grid;
  width: 38px;
  height: 38px;
  margin-bottom: 28px;
  place-items: center;
  border-radius: 50%;
  color: var(--white);
  background: var(--ink);
  font-size: 13px;
  font-weight: 800;
}

.feature-item p,
.guide-card p,
.faq-answer,
.prose p,
.prose li {
  color: var(--ink-soft);
}

.gallery-head,
.content-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 28px;
}

.gallery-head > p,
.content-head > p {
  max-width: 530px;
  margin: 0 0 28px;
  color: var(--ink-soft);
}

.preview-rail {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 20px;
  align-items: start;
}

.preview-item {
  margin: 0;
}

.preview-frame {
  padding: 9px;
  border-radius: 28px;
  background: #dfecea;
  box-shadow: 0 12px 30px rgba(11, 35, 48, 0.09);
}

.preview-item img {
  width: 100%;
  max-width: 400px;
  border-radius: 22px;
}

.preview-item figcaption {
  padding: 16px 4px 0;
  font-size: 14px;
  font-weight: 800;
}

.pathway-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.pathway {
  position: relative;
  min-height: 230px;
  padding: 32px;
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--white);
}

.pathway::after {
  position: absolute;
  right: -22px;
  bottom: -52px;
  color: var(--sky-soft);
  font-size: 150px;
  font-weight: 900;
  line-height: 1;
  content: attr(data-mark);
}

.pathway > * {
  position: relative;
  z-index: 1;
}

.pathway p {
  max-width: 430px;
  color: var(--ink-soft);
}

.text-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: #137e98;
  font-weight: 800;
}

.text-link::after {
  content: "→";
}

.review-grid {
  display: grid;
  grid-template-columns: 0.72fr 1.28fr;
  gap: 54px;
  align-items: center;
}

.score-number {
  display: block;
  color: var(--yellow);
  font-size: 72px;
  font-weight: 900;
  line-height: 1;
}

.review-list {
  display: grid;
  gap: 14px;
}

.review-item {
  padding: 22px 24px;
  border-left: 3px solid var(--green);
  background: rgba(255, 255, 255, 0.08);
}

.review-item blockquote {
  margin: 0 0 8px;
}

.review-item cite {
  color: #b8c8ca;
  font-size: 13px;
  font-style: normal;
}

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

.mini-faq article {
  padding: 26px;
  border: 1px solid var(--line);
  background: var(--white);
}

.mini-faq p {
  color: var(--ink-soft);
}

.download-band {
  padding: 44px 0;
  color: var(--ink);
  background: var(--yellow);
}

.download-band .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
}

.download-band h2 {
  margin: 0 0 8px;
  font-size: 30px;
}

.download-band p {
  margin: 0;
}

.page-hero {
  padding: 70px 0 56px;
  color: var(--white);
  background: var(--ink);
}

.page-hero h1 {
  max-width: 820px;
  margin-bottom: 16px;
  font-size: clamp(34px, 5vw, 56px);
}

.page-hero p {
  max-width: 760px;
  margin: 0;
  color: #c6d6d8;
  font-size: 17px;
}

.breadcrumb {
  margin: 0 0 18px;
  color: #8fd7e7;
  font-size: 13px;
}

.steps {
  display: grid;
  gap: 0;
  counter-reset: step;
}

.step {
  display: grid;
  grid-template-columns: 80px minmax(0, 1fr);
  gap: 24px;
  padding: 34px 0;
  border-bottom: 1px solid var(--line);
  counter-increment: step;
}

.step::before {
  display: grid;
  width: 58px;
  height: 58px;
  place-items: center;
  border-radius: 50%;
  color: var(--white);
  background: var(--sky);
  content: counter(step, decimal-leading-zero);
  font-weight: 900;
}

.step:nth-child(2n)::before {
  background: var(--green);
}

.step p {
  margin: 0 0 12px;
  color: var(--ink-soft);
}

.notice {
  padding: 22px 24px;
  border-left: 4px solid var(--yellow);
  background: #fff8df;
}

.notice strong {
  display: block;
  margin-bottom: 4px;
}

.check-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px 24px;
  padding: 0;
  list-style: none;
}

.check-list li {
  position: relative;
  padding-left: 28px;
}

.check-list li::before {
  position: absolute;
  left: 0;
  color: var(--green);
  content: "✓";
  font-weight: 900;
}

.prose {
  max-width: 850px;
}

.prose h2 {
  margin-top: 48px;
  margin-bottom: 18px;
  font-size: 30px;
}

.prose h3 {
  margin-top: 30px;
}

.prose a {
  color: #137e98;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.function-table {
  width: 100%;
  margin: 26px 0 42px;
  border-collapse: collapse;
  background: var(--white);
}

.function-table th,
.function-table td {
  padding: 17px 18px;
  border: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

.function-table th {
  color: var(--white);
  background: var(--ink);
}

.faq-list {
  display: grid;
  gap: 10px;
}

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

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

.faq-question::after {
  flex: 0 0 auto;
  color: var(--sky);
  content: "+";
  font-size: 25px;
}

.faq-question[aria-expanded="true"]::after {
  content: "−";
}

.faq-answer {
  padding: 0 22px 20px;
}

.faq-answer[hidden] {
  display: none;
}

.related-links {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.related-links a {
  padding: 22px;
  border: 1px solid var(--line);
  background: var(--white);
  font-weight: 800;
}

.site-footer {
  padding: 50px 0 28px;
  color: #c2d0d2;
  background: #071820;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.35fr 0.65fr 0.65fr;
  gap: 40px;
}

.site-footer .brand {
  color: var(--white);
}

.site-footer p {
  max-width: 520px;
  font-size: 13px;
}

.footer-title {
  margin: 0 0 14px;
  color: var(--white);
  font-weight: 800;
}

.footer-links {
  display: grid;
  gap: 9px;
  font-size: 14px;
}

.footer-links a:hover {
  color: var(--sky);
}

.copyright {
  margin-top: 34px;
  padding-top: 20px;
  border-top: 1px solid rgba(255, 255, 255, 0.11);
  font-size: 12px;
}

@media (max-width: 920px) {
  .menu-toggle {
    display: block;
  }

  .nav-links {
    position: fixed;
    top: 72px;
    right: 0;
    left: 0;
    display: none;
    min-height: calc(100vh - 72px);
    align-items: stretch;
    padding: 28px 20px;
    background: var(--paper);
    flex-direction: column;
  }

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

  .nav-links .button {
    width: 100%;
  }

  .hero-grid,
  .review-grid {
    grid-template-columns: 1fr;
  }

  .hero::before {
    top: auto;
    bottom: 0;
    width: 100%;
    height: 45%;
  }

  .hero-visual {
    max-width: 590px;
    min-height: 560px;
    margin-inline: auto;
  }

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

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

  .footer-grid > div:first-child {
    grid-column: 1 / -1;
  }
}

@media (max-width: 640px) {
  :root {
    --wrap: min(100% - 28px, 1160px);
  }

  .section {
    padding: 64px 0;
  }

  .hero {
    padding-top: 54px;
  }

  h1 {
    font-size: 42px;
  }

  .hero-grid {
    gap: 40px;
  }

  .hero-visual {
    min-height: 470px;
  }

  .phone-card.primary {
    right: 2%;
    width: 238px;
  }

  .phone-card.secondary {
    width: 180px;
  }

  .feature-grid,
  .preview-rail,
  .pathway-grid,
  .mini-faq,
  .check-list,
  .related-links,
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .gallery-head,
  .content-head,
  .download-band .container {
    align-items: flex-start;
    flex-direction: column;
  }

  .step {
    grid-template-columns: 56px minmax(0, 1fr);
    gap: 14px;
  }

  .step::before {
    width: 48px;
    height: 48px;
  }

  .function-table {
    display: block;
    overflow-x: auto;
  }

  .footer-grid > div:first-child {
    grid-column: auto;
  }
}

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

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
  }
}