:root {
  --ink: #171717;
  --paper: #f7f5ef;
  --white: #ffffff;
  --blue: #2145d8;
  --lime: #c8ff3d;
  --coral: #ff6b55;
  --line: #d7d4ca;
  --muted: #65645f;
  --max: 1180px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "微软雅黑", Arial, Helvetica, sans-serif;
  line-height: 1.7;
  letter-spacing: 0;
}
a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; height: auto; }
button { font: inherit; }

.content-rail, .nav-rail, .hero-rail { width: min(calc(100% - 48px), var(--max)); margin-inline: auto; }
.site-header { position: sticky; top: 0; z-index: 50; background: var(--paper); border-bottom: 1px solid var(--ink); }
.nav-rail { height: 72px; display: flex; align-items: center; justify-content: space-between; }
.brand { display: inline-flex; align-items: center; gap: 11px; font-weight: 800; white-space: nowrap; }
.brand img { width: 38px; height: 38px; border-radius: 4px; }
.main-nav { display: flex; align-items: center; gap: 30px; font-size: 14px; font-weight: 650; }
.main-nav a { position: relative; }
.main-nav a.is-active::after { content: ""; position: absolute; left: 0; right: 0; bottom: -8px; height: 3px; background: var(--blue); }
.main-nav .nav-download { padding: 9px 16px; color: var(--white); background: var(--ink); border: 1px solid var(--ink); border-radius: 4px; }
.main-nav .nav-download::after { display: none; }
.menu-toggle { display: none; width: 42px; height: 42px; border: 1px solid var(--ink); background: transparent; border-radius: 4px; cursor: pointer; }

.hero { border-bottom: 1px solid var(--ink); overflow: hidden; }
.hero-rail { min-height: 606px; display: grid; grid-template-columns: minmax(0, 1.04fr) minmax(360px, .96fr); align-items: center; gap: 72px; padding-block: 42px 40px; }
.index-tag, .step-label { display: inline-flex; align-items: center; min-height: 26px; padding: 2px 9px; background: var(--lime); border: 1px solid var(--ink); font-size: 12px; font-weight: 800; text-transform: uppercase; }
.hero h1 { max-width: 650px; margin: 22px 0 18px; font-size: 54px; line-height: 1.12; letter-spacing: 0; }
.hero-copy > p { max-width: 610px; margin: 0; color: #3c3b37; font-size: 17px; }
.hero-actions { display: flex; align-items: center; gap: 24px; margin-top: 28px; }
.primary-button { display: inline-flex; align-items: center; justify-content: center; min-width: 128px; min-height: 48px; padding: 10px 24px; color: var(--white); background: var(--blue); border: 1px solid var(--ink); border-radius: 4px; font-weight: 800; box-shadow: 4px 4px 0 var(--ink); }
.primary-button:hover { transform: translate(2px, 2px); box-shadow: 2px 2px 0 var(--ink); }
.text-link { display: inline-flex; align-items: center; gap: 8px; font-weight: 800; border-bottom: 2px solid var(--ink); }
.hero-ledger { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 31px; }
.hero-ledger span { padding: 4px 9px; border: 1px solid var(--ink); background: var(--white); font-size: 12px; font-weight: 750; }
.hero-media { position: relative; min-height: 500px; display: flex; align-items: center; justify-content: center; }
.screen-frame { position: relative; z-index: 2; padding: 10px; background: var(--ink); border-radius: 5px; box-shadow: 15px 15px 0 var(--coral); }
.hero-screen { width: auto; height: 452px; max-width: 400px; object-fit: contain; border-radius: 2px; }
.catalog-slip { position: absolute; display: flex; justify-content: space-between; padding: 10px 12px; color: var(--ink); background: var(--lime); border: 1px solid var(--ink); font-size: 11px; font-weight: 800; text-transform: uppercase; }
.slip-top { width: 220px; top: 14px; left: 5px; transform: rotate(-4deg); }
.slip-side { width: 152px; right: -10px; bottom: 30px; background: var(--white); transform: rotate(5deg); }

.section { padding-block: 82px; border-bottom: 1px solid var(--ink); }
.section-heading { display: flex; align-items: baseline; gap: 18px; margin-bottom: 34px; }
.section-number { color: var(--blue); font-size: 13px; font-weight: 850; }
.section h2, .download-band h2 { margin: 0; font-size: 34px; line-height: 1.25; }
.gallery-section { background: var(--white); }
.gallery-grid { display: grid; grid-template-columns: 1.1fr 1fr 1fr; gap: 18px; align-items: end; }
.preview-card { margin: 0; border: 1px solid var(--ink); background: var(--paper); border-radius: 5px; overflow: hidden; }
.preview-image { height: 330px; display: grid; place-items: center; padding: 22px; background: #e9e7df; border-bottom: 1px solid var(--ink); }
.preview-card-large .preview-image { height: 390px; }
.preview-image img { width: auto; max-width: 400px; height: 100%; object-fit: contain; }
.preview-card figcaption { display: grid; gap: 3px; min-height: 84px; padding: 14px 16px; }
.preview-card figcaption span { color: var(--muted); font-size: 13px; }
.features-section { background: var(--lime); }
.feature-list { border-top: 1px solid var(--ink); }
.feature-list article { display: grid; grid-template-columns: 70px 220px 1fr; gap: 24px; align-items: baseline; padding: 24px 0; border-bottom: 1px solid var(--ink); }
.feature-list article > span { color: var(--blue); font-size: 13px; font-weight: 850; }
.feature-list h3, .feature-list p { margin: 0; }
.feature-list h3 { font-size: 20px; }
.feature-list p { color: #353530; }
.route-section { background: var(--paper); }
.route-grid { display: grid; grid-template-columns: .78fr 1.22fr; gap: 80px; }
.route-copy h2 { margin: 8px 0 16px; }
.route-description { margin: 0 0 22px; color: var(--muted); }
.route-steps { margin: 0; padding: 0; list-style: none; border-top: 1px solid var(--ink); }
.route-steps li { display: grid; grid-template-columns: 130px 1fr; gap: 24px; padding: 20px 0; border-bottom: 1px solid var(--ink); }
.route-steps span { color: var(--muted); }
.faq-preview-section { background: var(--white); }
.faq-preview-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.faq-preview-grid a { display: grid; gap: 8px; min-height: 132px; padding: 22px; border: 1px solid var(--ink); border-radius: 5px; background: var(--paper); }
.faq-preview-grid a:hover { background: var(--coral); }
.faq-preview-grid span { color: var(--muted); font-size: 14px; }
.download-band { padding: 44px 0; color: var(--white); background: var(--ink); }
.download-inner { display: flex; align-items: center; justify-content: space-between; gap: 40px; }
.download-inner span { color: var(--lime); font-size: 12px; font-weight: 850; }
.download-inner .primary-button { color: var(--ink); background: var(--lime); box-shadow: 4px 4px 0 var(--coral); }
.site-footer { padding: 30px 0; text-align: center; background: var(--paper); }
.site-footer p { margin: 4px 0; color: var(--muted); font-size: 13px; text-align: center; }

.inner-hero { padding: 64px 0 58px; color: var(--white); background: var(--blue); border-bottom: 1px solid var(--ink); }
.inner-hero-grid { display: grid; grid-template-columns: 1.15fr .85fr; gap: 70px; align-items: end; }
.inner-hero .index-tag { color: var(--ink); }
.inner-hero h1 { margin: 20px 0 14px; font-size: 48px; line-height: 1.15; }
.inner-hero p { max-width: 690px; margin: 0; color: #f0f2ff; }
.inner-index { display: grid; justify-items: end; gap: 6px; padding: 20px 0 0; border-top: 1px solid rgba(255,255,255,.7); }
.inner-index b { color: var(--lime); font-size: 42px; line-height: 1; }
.inner-index span { font-size: 13px; }
.faq-hero { background: var(--ink); }
.article-section, .faq-section { padding: 66px 0 84px; }
.article-layout { display: grid; grid-template-columns: 220px minmax(0, 760px); gap: 88px; justify-content: start; }
.article-nav { position: sticky; top: 104px; align-self: start; display: grid; border-top: 4px solid var(--coral); }
.article-nav b { padding: 13px 0; font-size: 12px; }
.article-nav a { padding: 9px 0; border-top: 1px solid var(--line); color: var(--muted); font-size: 14px; }
.article-content section { scroll-margin-top: 104px; padding: 0 0 42px; margin: 0 0 42px; border-bottom: 1px solid var(--line); }
.article-content h2 { margin: 11px 0 20px; font-size: 30px; line-height: 1.3; }
.article-content p { margin: 0 0 16px; color: #41403c; }
.article-content a:not(.primary-button) { color: var(--blue); text-decoration: underline; }
.article-action { margin: 26px 0 8px; }

.faq-tools { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 28px; }
.filter-button { min-width: 76px; min-height: 40px; padding: 7px 16px; border: 1px solid var(--ink); border-radius: 4px; background: var(--white); cursor: pointer; font-weight: 750; }
.filter-button.is-active { color: var(--white); background: var(--blue); }
.faq-list { border-top: 1px solid var(--ink); }
.faq-list details { border-bottom: 1px solid var(--ink); background: transparent; }
.faq-list details[hidden] { display: none; }
.faq-list summary { position: relative; cursor: pointer; list-style: none; padding: 23px 58px 23px 0; font-size: 18px; font-weight: 800; }
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary::after { content: "+"; position: absolute; right: 12px; top: 16px; width: 32px; height: 32px; display: grid; place-items: center; border: 1px solid var(--ink); border-radius: 50%; font-size: 21px; }
.faq-list details[open] summary::after { content: "−"; background: var(--lime); }
.faq-list details p { max-width: 880px; margin: -4px 0 24px; color: #45443f; }
.faq-list details a { color: var(--blue); text-decoration: underline; }
.faq-empty { padding: 30px 0; color: var(--muted); }

@media (max-width: 900px) {
  .hero-rail { grid-template-columns: 1fr 330px; gap: 28px; }
  .hero h1 { font-size: 46px; }
  .gallery-grid { grid-template-columns: repeat(3, 1fr); }
  .preview-image, .preview-card-large .preview-image { height: 300px; }
}

@media (max-width: 720px) {
  .content-rail, .nav-rail, .hero-rail { width: min(calc(100% - 32px), var(--max)); }
  .nav-rail { height: 64px; }
  .menu-toggle { display: grid; place-items: center; }
  .main-nav { position: absolute; top: 64px; left: 16px; right: 16px; display: none; padding: 10px; background: var(--paper); border: 1px solid var(--ink); box-shadow: 5px 5px 0 var(--ink); }
  .main-nav.is-open { display: grid; }
  .main-nav a { padding: 10px 9px; }
  .main-nav a.is-active::after { display: none; }
  .main-nav .nav-download { text-align: center; }
  .hero-rail { min-height: 0; grid-template-columns: 1fr; gap: 18px; padding-block: 30px 28px; }
  .hero h1 { margin: 14px 0 12px; font-size: 38px; line-height: 1.16; }
  .hero-copy > p { font-size: 15px; line-height: 1.65; }
  .hero-actions { margin-top: 20px; }
  .hero-ledger { margin-top: 20px; }
  .hero-media { min-height: 316px; }
  .hero-screen { height: 290px; }
  .screen-frame { padding: 7px; box-shadow: 9px 9px 0 var(--coral); }
  .slip-top { width: 170px; top: 3px; left: 0; }
  .slip-side { right: 0; bottom: 2px; }
  .section { padding-block: 58px; }
  .section-heading { margin-bottom: 26px; }
  .section h2, .download-band h2 { font-size: 28px; }
  .gallery-grid { grid-template-columns: 1fr; gap: 14px; }
  .preview-image, .preview-card-large .preview-image { height: 330px; }
  .feature-list article { grid-template-columns: 42px 1fr; gap: 12px; }
  .feature-list article p { grid-column: 2; }
  .route-grid { grid-template-columns: 1fr; gap: 38px; }
  .faq-preview-grid { grid-template-columns: 1fr; }
  .download-inner { align-items: flex-start; flex-direction: column; gap: 24px; }
  .inner-hero { padding: 44px 0; }
  .inner-hero-grid { grid-template-columns: 1fr; gap: 30px; }
  .inner-hero h1 { font-size: 36px; }
  .inner-index { justify-items: start; }
  .article-layout { grid-template-columns: 1fr; gap: 40px; }
  .article-nav { position: static; grid-template-columns: repeat(2, 1fr); }
  .article-nav b { grid-column: 1 / -1; }
  .article-nav a { padding-right: 8px; }
  .article-section, .faq-section { padding: 50px 0 64px; }
  .article-content h2 { font-size: 26px; }
}

@media (max-width: 390px) {
  .hero h1 { font-size: 35px; }
  .hero-actions { align-items: flex-start; flex-direction: column; gap: 14px; }
  .hero-screen { height: 270px; }
  .hero-media { min-height: 296px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; }
}