:root {
  --ink: #18212f;
  --muted: #5d6878;
  --line: #dce3ea;
  --soft: #f4f7f9;
  --surface: #ffffff;
  --primary: #176c88;
  --primary-dark: #0f5269;
  --status: #287357;
  --navy: #17314a;
  --shadow: 0 18px 50px rgba(24, 33, 47, 0.1);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "微软雅黑", Arial, Helvetica, sans-serif;
  color: var(--ink);
  background: var(--surface);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--surface); color: var(--ink); line-height: 1.7; }
a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; height: auto; }
button { font: inherit; }

.site-header { position: sticky; top: 0; z-index: 50; background: rgba(255,255,255,0.96); border-bottom: 1px solid var(--line); backdrop-filter: blur(12px); }
.header-inner, .hero-inner, .section-inner, .sub-hero-inner, .faq-hero-inner, .download-band, .footer-inner { width: min(1180px, calc(100% - 48px)); margin: 0 auto; }
.header-inner { min-height: 76px; display: flex; align-items: center; gap: 28px; }
.brand { display: inline-flex; align-items: center; gap: 11px; font-size: 18px; font-weight: 800; white-space: nowrap; }
.brand img { width: 44px; height: 44px; border-radius: 12px; }
.site-nav { display: flex; align-items: center; gap: 26px; margin-left: auto; }
.site-nav a { color: #465365; font-size: 15px; font-weight: 650; padding: 26px 0 22px; border-bottom: 3px solid transparent; }
.site-nav a:hover, .site-nav a.active { color: var(--primary); border-bottom-color: var(--primary); }
.header-actions { display: flex; align-items: center; gap: 14px; }
.text-action { color: var(--primary-dark); font-weight: 750; font-size: 14px; white-space: nowrap; }
.menu-toggle { display: none; border: 0; background: transparent; font-size: 24px; color: var(--ink); }

.button { min-height: 48px; display: inline-flex; align-items: center; justify-content: center; padding: 0 24px; border: 1px solid var(--primary); border-radius: 6px; color: #fff; background: var(--primary); font-weight: 800; transition: transform .2s ease, background .2s ease; }
.button:hover { transform: translateY(-2px); background: var(--primary-dark); }
.button-small { min-height: 40px; padding: 0 17px; font-size: 14px; }
.button-secondary { background: #fff; color: var(--primary-dark); border-color: #91afba; }
.button-secondary:hover { color: #fff; }
.button-light { background: #fff; color: var(--navy); border-color: #fff; }
.button-light:hover { background: #eef5f7; color: var(--navy); }
.button-outline { background: transparent; border-color: rgba(255,255,255,.6); }

.hero { background: linear-gradient(110deg, #f5f9fa 0 62%, #e8f2f3 62%); border-bottom: 1px solid var(--line); }
.hero-inner { min-height: 660px; display: grid; grid-template-columns: minmax(0, 1.02fr) minmax(440px, .98fr); gap: 72px; align-items: center; padding: 58px 0 62px; }
.eyebrow { color: var(--primary); font-size: 12px; letter-spacing: 0; font-weight: 900; }
.hero h1, .sub-hero h1, .faq-hero h1 { margin: 18px 0 20px; line-height: 1.12; letter-spacing: 0; }
.hero h1 { max-width: 620px; font-size: 52px; }
.hero-copy > p { max-width: 660px; color: var(--muted); font-size: 17px; margin: 0; }
.hero-actions { display: flex; gap: 12px; margin-top: 30px; }
.hero-facts { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0; margin: 36px 0 0; border-top: 1px solid var(--line); padding-top: 18px; }
.hero-facts div { padding-right: 18px; }
.hero-facts dt { color: #718090; font-size: 12px; }
.hero-facts dd { margin: 2px 0 0; font-size: 14px; font-weight: 800; }
.hero-media { position: relative; min-height: 510px; display: flex; align-items: center; justify-content: center; }
.hero-screen { max-width: 400px; box-shadow: var(--shadow); border: 1px solid rgba(24,33,47,.12); }
.hero-screen-main { width: min(72%, 330px); border-radius: 20px; }
.hero-screen-float { position: absolute; width: min(58%, 275px); left: 0; bottom: 32px; border-radius: 16px; }
.media-label { position: absolute; top: 22px; right: 5px; padding: 8px 12px; background: #fff; border: 1px solid var(--line); border-radius: 6px; color: var(--status); font-size: 12px; font-weight: 850; }
.media-index { position: absolute; right: 0; bottom: 44px; display: grid; text-align: right; }
.media-index strong { font-size: 30px; color: var(--primary-dark); }
.media-index span { color: var(--muted); font-size: 12px; }

.section { padding: 88px 0; }
.section-heading { margin-bottom: 34px; }
.section-heading h2 { margin: 0; font-size: 34px; line-height: 1.2; letter-spacing: 0; }
.feature-section { background: #fff; }
.feature-grid { display: grid; grid-template-columns: repeat(4, 1fr); border: 1px solid var(--line); }
.feature-card { padding: 30px 26px; min-height: 260px; border-right: 1px solid var(--line); }
.feature-card:last-child { border-right: 0; }
.feature-number { color: var(--primary); font-weight: 900; font-size: 13px; }
.feature-card h3 { margin: 28px 0 9px; font-size: 20px; }
.feature-card p { margin: 0; color: var(--muted); font-size: 14px; }

.gallery-section { background: var(--soft); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.gallery-layout { display: grid; grid-template-columns: 1.35fr .82fr .82fr; gap: 20px; align-items: stretch; }
.gallery-layout figure { margin: 0; background: #fff; border: 1px solid var(--line); border-radius: 6px; padding: 18px; display: flex; flex-direction: column; justify-content: center; }
.gallery-layout img { width: 100%; max-width: 400px; margin: auto; object-fit: contain; }
.gallery-wide img { border-radius: 6px; }
.gallery-layout figcaption { margin-top: 14px; color: var(--muted); font-size: 13px; text-align: center; }

.scenario-layout { display: grid; grid-template-columns: .82fr 1.18fr; gap: 80px; align-items: start; }
.scenario-copy { position: sticky; top: 120px; }
.scenario-copy p { color: var(--muted); }
.inline-link { color: var(--primary-dark); font-weight: 800; }
.scenario-list { border-top: 1px solid var(--line); }
.scenario-list article { padding: 28px 0; border-bottom: 1px solid var(--line); display: grid; grid-template-columns: 120px 1fr; column-gap: 22px; }
.scenario-list span { grid-row: span 2; color: var(--status); font-size: 13px; font-weight: 850; }
.scenario-list h3 { margin: 0 0 6px; font-size: 19px; }
.scenario-list p { margin: 0; color: var(--muted); font-size: 14px; }

.route-section { padding-top: 0; }
.route-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.route-card { padding: 38px; border: 1px solid var(--line); border-radius: 6px; background: #f0f6f7; }
.route-card-dark { background: var(--navy); color: #fff; border-color: var(--navy); }
.route-card > span { color: var(--primary); font-size: 12px; font-weight: 900; }
.route-card-dark > span { color: #8dc8d5; }
.route-card h2 { margin: 12px 0 10px; }
.route-description { color: var(--muted); margin-bottom: 16px; }
.route-card-dark .route-description { color: #c8d5df; }
.route-card a { font-weight: 850; color: var(--primary-dark); }
.route-card-dark a { color: #fff; }

.faq-preview { padding-top: 0; }
.preview-list { border-top: 1px solid var(--line); }
.preview-list a { display: flex; justify-content: space-between; padding: 22px 4px; border-bottom: 1px solid var(--line); font-weight: 720; }
.preview-list b { color: var(--primary); }

.download-band { margin-top: 20px; margin-bottom: 88px; padding: 44px 48px; background: var(--primary-dark); color: #fff; display: flex; align-items: center; justify-content: space-between; gap: 30px; border-radius: 6px; }
.download-band span { color: #a9d6df; font-size: 13px; font-weight: 800; }
.download-band h2 { margin: 5px 0 0; font-size: 28px; }
.download-band-actions { display: flex; gap: 12px; flex-shrink: 0; }

.site-footer { border-top: 1px solid var(--line); background: #f7f9fa; }
.footer-inner { padding: 34px 0; text-align: center; }
.footer-brand { display: inline-flex; align-items: center; gap: 9px; }
.footer-brand img { border-radius: 10px; }
.footer-inner p { margin: 15px auto 8px; color: var(--muted); font-size: 13px; max-width: 760px; text-align: center; }
.footer-inner small { color: #7a8694; }

.sub-hero { background: #eef5f6; border-bottom: 1px solid var(--line); }
.sub-hero-inner { min-height: 430px; display: grid; grid-template-columns: 1.2fr .8fr; gap: 70px; align-items: center; padding: 52px 0; }
.sub-hero h1, .faq-hero h1 { font-size: 45px; }
.sub-hero p, .faq-hero p { color: var(--muted); font-size: 17px; max-width: 720px; }
.sub-hero img { max-width: 360px; max-height: 270px; object-fit: contain; justify-self: end; border-radius: 12px; box-shadow: var(--shadow); }
.article-layout { width: min(1120px, calc(100% - 48px)); margin: 0 auto; display: grid; grid-template-columns: 220px minmax(0, 1fr); gap: 72px; padding: 72px 0 100px; }
.article-nav { position: sticky; top: 108px; align-self: start; display: grid; border-left: 2px solid var(--line); }
.article-nav strong, .article-nav a { padding: 7px 0 7px 18px; }
.article-nav a { color: var(--muted); font-size: 14px; }
.article-nav a:hover { color: var(--primary); }
.article-content section { padding-bottom: 40px; margin-bottom: 42px; border-bottom: 1px solid var(--line); scroll-margin-top: 110px; }
.article-content h2 { margin: 8px 0 14px; font-size: 28px; }
.article-content p, .article-content li { color: #465365; }
.step-tag { color: var(--primary); font-size: 12px; font-weight: 900; }
.notice { padding: 22px 24px; background: #edf6f2; border-left: 4px solid var(--status); }
.notice p { margin-bottom: 0; }
.article-content li { margin-bottom: 8px; }
.article-next, .faq-help { display: flex; align-items: center; justify-content: space-between; gap: 24px; padding: 30px; background: var(--soft); border: 1px solid var(--line); border-radius: 6px; }
.article-next span, .faq-help span { color: var(--primary); font-size: 12px; font-weight: 900; }
.article-next h2, .faq-help h2 { margin: 5px 0 0; font-size: 22px; }

.faq-hero { background: var(--navy); color: #fff; }
.faq-hero-inner { padding: 74px 0 76px; }
.faq-hero p { color: #ccd8e2; }
.faq-stats { display: flex; gap: 28px; margin-top: 30px; }
.faq-stats span { color: #dce7ee; }
.faq-stats strong { color: #fff; font-size: 24px; margin-right: 7px; }
.faq-shell { width: min(980px, calc(100% - 48px)); margin: 0 auto; padding: 76px 0 100px; }
.faq-category { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; align-items: end; margin-top: 66px; margin-bottom: 18px; }
.faq-category:first-child { margin-top: 0; }
.faq-category h2 { margin: 0; font-size: 28px; }
.faq-category p { margin: 0; color: var(--muted); text-align: right; }
.accordion-list { border-top: 1px solid var(--line); }
.accordion-item { border-bottom: 1px solid var(--line); scroll-margin-top: 100px; }
.accordion-item button { width: 100%; padding: 22px 0; border: 0; background: transparent; display: flex; justify-content: space-between; text-align: left; color: var(--ink); font-weight: 800; cursor: pointer; }
.accordion-item button b { color: var(--primary); font-size: 20px; }
.accordion-content { display: none; padding: 0 40px 24px 0; }
.accordion-item button[aria-expanded="true"] + .accordion-content { display: block; }
.accordion-content p { margin: 0; color: var(--muted); }
.faq-help { margin-top: 68px; }

@media (max-width: 980px) {
  .header-inner { flex-wrap: wrap; min-height: 70px; padding: 12px 0; }
  .menu-toggle { display: block; margin-left: auto; }
  .site-nav { display: none; order: 4; width: 100%; margin: 0; flex-direction: column; align-items: stretch; gap: 0; border-top: 1px solid var(--line); }
  .site-nav.open { display: flex; }
  .site-nav a { padding: 11px 2px; border-bottom-width: 1px; }
  .header-actions { display: none; }
  .hero-inner { grid-template-columns: 1fr 420px; gap: 30px; }
  .hero h1 { font-size: 43px; }
  .feature-grid { grid-template-columns: 1fr 1fr; }
  .feature-card:nth-child(2) { border-right: 0; }
  .feature-card:nth-child(-n+2) { border-bottom: 1px solid var(--line); }
  .gallery-layout { grid-template-columns: 1fr 1fr; }
  .gallery-wide { grid-column: span 2; }
}

@media (max-width: 720px) {
  .header-inner, .hero-inner, .section-inner, .sub-hero-inner, .faq-hero-inner, .download-band, .footer-inner, .article-layout, .faq-shell { width: min(100% - 32px, 620px); }
  .brand img { width: 40px; height: 40px; }
  .hero { background: #f5f9fa; }
  .hero-inner { min-height: auto; grid-template-columns: 1fr; gap: 26px; padding: 42px 0 44px; }
  .hero h1 { font-size: 38px; margin-top: 12px; }
  .hero-copy > p { font-size: 15px; }
  .hero-actions { flex-direction: row; margin-top: 22px; }
  .hero-actions .button { width: auto; flex: 1; padding: 0 12px; }
  .download-band-actions { flex-direction: column; }
  .download-band-actions .button { width: 100%; }
  .hero-facts { display: none; }
  .hero-media { min-height: 270px; order: 2; }
  .hero-screen-main { width: 52%; max-height: 230px; object-fit: contain; }
  .hero-screen-float { width: 43%; bottom: 12px; }
  .media-label { top: 8px; }
  .media-index { bottom: 12px; }
  .section { padding: 62px 0; }
  .section-heading h2 { font-size: 28px; }
  .feature-grid { grid-template-columns: 1fr; }
  .feature-card { min-height: auto; border-right: 0; border-bottom: 1px solid var(--line); }
  .feature-card:last-child { border-bottom: 0; }
  .gallery-layout { grid-template-columns: 1fr; }
  .gallery-wide { grid-column: auto; }
  .scenario-layout, .route-grid { grid-template-columns: 1fr; gap: 28px; }
  .scenario-copy { position: static; }
  .scenario-list article { grid-template-columns: 1fr; }
  .scenario-list span { grid-row: auto; margin-bottom: 8px; }
  .download-band { margin-bottom: 62px; padding: 30px 24px; align-items: stretch; flex-direction: column; }
  .download-band h2 { font-size: 23px; }
  .sub-hero-inner { min-height: auto; grid-template-columns: 1fr; gap: 28px; padding: 46px 0; }
  .sub-hero h1, .faq-hero h1 { font-size: 35px; }
  .sub-hero img { justify-self: center; max-width: 290px; max-height: 210px; }
  .article-layout { grid-template-columns: 1fr; gap: 34px; padding-top: 44px; }
  .article-nav { position: static; grid-template-columns: 1fr 1fr; border-left: 0; border-top: 2px solid var(--line); padding-top: 12px; }
  .article-nav strong { grid-column: span 2; padding-left: 0; }
  .article-nav a { padding-left: 0; }
  .article-next, .faq-help { align-items: stretch; flex-direction: column; }
  .faq-hero-inner { padding: 54px 0; }
  .faq-category { grid-template-columns: 1fr; gap: 4px; }
  .faq-category p { text-align: left; }
}

@media (max-width: 390px) {
  .hero h1, .sub-hero h1, .faq-hero h1 { font-size: 32px; }
  .hero-facts { grid-template-columns: 1fr; }
  .hero-facts div { display: flex; justify-content: space-between; }
  .hero-media { min-height: 250px; }
  .media-index { display: none; }
}