:root {
  --paper: #f7f5ef;
  --white: #ffffff;
  --ink: #181817;
  --muted: #68655e;
  --line: #cbc7bc;
  --red: #9f1c25;
  --red-dark: #72131a;
  --yellow: #f2c94c;
  --green: #1f6a4f;
  --green-dark: #134936;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 82px; }
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;
}
a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; height: auto; }
button, a { -webkit-tap-highlight-color: transparent; }
button { font: inherit; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  min-height: 72px;
  background: rgba(247, 245, 239, 0.97);
  border-bottom: 1px solid var(--ink);
}
.header-inner {
  width: 100%;
  max-width: 1320px;
  min-height: 71px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  margin: 0 auto;
  padding: 10px 24px;
}
.brand { display: inline-flex; align-items: center; gap: 10px; font-size: 22px; font-weight: 900; text-transform: lowercase; }
.brand img { width: 42px; height: 42px; object-fit: contain; }
.site-nav { display: flex; align-items: center; gap: clamp(14px, 2vw, 30px); font-size: 14px; font-weight: 700; }
.site-nav a { position: relative; padding: 7px 0; }
.site-nav a:not(.nav-download)::after { content: ""; position: absolute; left: 0; right: 100%; bottom: 2px; height: 2px; background: var(--red); transition: right .2s ease; }
.site-nav a:hover::after, .site-nav a.is-current::after { right: 0; }
.site-nav .nav-download { padding: 8px 16px; color: var(--white); background: var(--green); }
.menu-button { display: none; width: 42px; height: 42px; padding: 0; border: 1px solid var(--ink); background: var(--paper); font-size: 21px; cursor: pointer; }

.hero {
  position: relative;
  width: calc(100% - 48px);
  max-width: 1320px;
  min-height: 610px;
  display: grid;
  grid-template-columns: minmax(460px, 1.12fr) minmax(330px, .88fr);
  align-items: stretch;
  margin: 0 auto;
  border-right: 1px solid var(--ink);
  border-bottom: 1px solid var(--ink);
  border-left: 1px solid var(--ink);
  overflow: hidden;
}
.hero-device {
  min-height: 610px;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  padding: 38px 38px 26px;
  background: var(--red);
  border-left: 1px solid var(--ink);
}
.hero-device::before { content: ""; position: absolute; inset: 18px; border: 1px dashed rgba(255,255,255,.55); }
.hero-device img { position: relative; z-index: 1; width: min(60%, 270px); max-width: 400px; filter: drop-shadow(13px 15px 0 rgba(24,24,23,.32)); }
.device-label { position: absolute; z-index: 2; top: 30px; left: 32px; color: var(--white); font-size: 11px; font-weight: 900; letter-spacing: 0; }
.hero-copy {
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 52px clamp(48px, 5vw, 72px) 72px;
  background: linear-gradient(90deg, transparent 49px, rgba(24,24,23,.09) 50px, transparent 51px), var(--paper);
  background-size: 52px 100%;
}
.eyebrow { display: block; color: var(--green-dark); font-size: 12px; font-weight: 900; text-transform: uppercase; }
h1, h2, h3, p { margin-top: 0; }
.hero h1 { max-width: 690px; margin: 14px 0 18px; font-size: clamp(48px, 5.4vw, 76px); line-height: .98; font-weight: 950; }
.hero-title-line { display: block; }
.hero-copy > p { max-width: 680px; margin-bottom: 24px; font-size: 17px; line-height: 1.9; }
.hero-actions { display: flex; align-items: center; gap: 24px; }
.button { display: inline-flex; min-height: 46px; align-items: center; justify-content: center; padding: 11px 24px; border: 1px solid var(--ink); font-weight: 900; transition: transform .2s ease, box-shadow .2s ease; }
.button:hover { transform: translate(-3px, -3px); box-shadow: 5px 5px 0 var(--ink); }
.button-primary { color: var(--white); background: var(--green); }
.text-link { padding: 8px 0; font-size: 14px; font-weight: 800; border-bottom: 2px solid var(--red); }
.alphabet-rail { display: grid; grid-template-columns: repeat(10, minmax(30px, 1fr)); max-width: 700px; margin-top: 40px; border: 1px solid var(--ink); background: var(--white); }
.alphabet-rail span { display: grid; min-height: 45px; place-items: center; font-weight: 900; border-right: 1px solid var(--ink); }
.alphabet-rail span:nth-child(4n+1) { background: var(--yellow); }
.alphabet-rail span:last-child { border-right: 0; color: var(--white); background: var(--red); }
.next-shelf { position: absolute; left: 0; right: 0; bottom: 0; height: 52px; display: flex; align-items: center; justify-content: center; color: var(--white); background: var(--ink); font-size: 12px; font-weight: 900; text-transform: uppercase; }

.section-band { padding: clamp(68px, 8vw, 112px) clamp(20px, 5vw, 78px); border-bottom: 1px solid var(--ink); }
.section-heading { display: grid; grid-template-columns: 58px minmax(220px, .7fr) 1fr; align-items: end; gap: 22px; max-width: 1400px; margin: 0 auto 48px; padding-bottom: 18px; border-bottom: 2px solid var(--ink); }
.section-number { width: 46px; height: 46px; display: grid; place-items: center; color: var(--ink); background: var(--yellow); font-size: 13px; font-weight: 900; }
.section-heading h2 { margin: 0; font-size: clamp(30px, 4vw, 54px); line-height: 1; }
.section-note { justify-self: end; max-width: 430px; color: var(--muted); font-size: 14px; text-align: right; }

.creator-index { background: var(--white); }
.creator-row { max-width: 1400px; margin: 0 auto; display: grid; grid-template-columns: repeat(4, 1fr); border-top: 1px solid var(--ink); border-bottom: 1px solid var(--ink); }
.creator-entry { min-height: 300px; padding: 28px; border-right: 1px solid var(--ink); }
.creator-entry:last-child { border-right: 0; }
.creator-letter { display: block; color: var(--red); font-size: 78px; line-height: 1; font-weight: 950; }
.creator-entry h3 { margin: 32px 0 8px; font-size: 21px; }
.creator-entry p { margin: 0; color: var(--muted); font-size: 14px; }

.features { background: var(--paper); }
.feature-list { max-width: 1400px; margin: 0 auto; display: grid; grid-template-columns: 1fr 1fr; border: 1px solid var(--ink); }
.feature-list article { min-height: 250px; padding: 34px; border-right: 1px solid var(--ink); border-bottom: 1px solid var(--ink); background: var(--white); }
.feature-list article:nth-child(2n) { border-right: 0; }
.feature-list article:nth-last-child(-n+2) { border-bottom: 0; }
.feature-list article:nth-child(3) { background: var(--yellow); }
.feature-list article:nth-child(4) { color: var(--white); background: var(--green-dark); }
.feature-list article > span { font-size: 11px; font-weight: 900; }
.feature-list h3 { margin: 52px 0 10px; font-size: 25px; }
.feature-list p { max-width: 580px; margin-bottom: 0; }

.gallery { color: var(--white); background: var(--ink); }
.light-heading { border-color: var(--white); }
.light-heading .section-number { color: var(--ink); }
.light-heading .section-note { color: #c9c6bd; }
.gallery-strip { max-width: 1250px; margin: 0 auto; display: grid; grid-template-columns: repeat(3, 1fr); gap: clamp(24px, 4vw, 62px); }
.gallery figure { margin: 0; }
.image-mount { position: relative; min-height: 590px; display: flex; align-items: center; justify-content: center; padding: 24px; border: 1px solid #6e6b63; background: #262624; }
.image-mount::before { content: "+"; position: absolute; top: 8px; left: 12px; color: var(--yellow); font-weight: 900; }
.image-mount img { width: min(100%, 330px); max-width: 400px; box-shadow: 12px 12px 0 var(--red); }
.gallery figcaption { display: flex; justify-content: space-between; gap: 16px; padding: 17px 0; border-bottom: 1px dashed #77736b; }
.gallery figcaption b { font-size: 15px; }
.gallery figcaption span { color: #c9c6bd; font-size: 12px; text-align: right; }

.reading-notes { background: var(--white); }
.route-list { max-width: 1400px; margin: 0 auto; padding: 0; list-style: none; border-top: 1px solid var(--ink); }
.route-list li { display: grid; grid-template-columns: 34px minmax(180px, .45fr) 1fr; gap: 24px; padding: 25px 0; border-bottom: 1px solid var(--ink); counter-increment: route; }
.route-list { counter-reset: route; }
.route-list li::before { content: counter(route, decimal-leading-zero); color: var(--red); font-size: 12px; font-weight: 900; }
.route-list span { font-size: 21px; font-weight: 900; }
.route-list p { margin: 0; color: var(--muted); }

.deep-links { background: var(--paper); }
.link-shelves { max-width: 1400px; margin: 0 auto; border-top: 1px solid var(--ink); }
.link-shelves a { display: grid; grid-template-columns: 180px 1fr 1fr; align-items: center; gap: 28px; min-height: 120px; padding: 24px; border-bottom: 1px solid var(--ink); transition: background .2s ease, color .2s ease; }
.link-shelves a:hover { color: var(--white); background: var(--green-dark); }
.link-shelves span { font-size: 11px; font-weight: 900; }
.link-shelves strong { font-size: 23px; }
.link-shelves small { color: var(--muted); }
.link-shelves a:hover small { color: #d8e7df; }

.download-band { display: flex; align-items: center; justify-content: space-between; gap: 28px; padding: 54px clamp(20px, 5vw, 78px); color: var(--white); background: var(--red); border-bottom: 1px solid var(--ink); }
.download-band .eyebrow { color: #ffd9dc; }
.download-band h2 { margin: 8px 0 0; font-size: clamp(27px, 4vw, 48px); line-height: 1.2; }
.download-band .button-primary { flex: 0 0 auto; color: var(--ink); background: var(--yellow); }

.site-footer { padding: 48px 20px 34px; color: #ddd9d0; background: var(--ink); text-align: center; }
.footer-brand { display: inline-flex; align-items: center; gap: 10px; color: var(--white); font-weight: 900; }
.footer-brand img { width: 40px; height: 40px; }
.site-footer nav { display: flex; justify-content: center; gap: 24px; margin: 22px 0; font-size: 13px; }
.site-footer p { max-width: 780px; margin: 18px auto; font-size: 13px; text-align: center; }
.site-footer small { display: block; text-align: center; }

.internal-hero { min-height: 460px; display: flex; flex-direction: column; justify-content: center; align-items: flex-start; padding: 72px clamp(20px, 8vw, 120px); border-bottom: 1px solid var(--ink); }
.internal-hero h1 { max-width: 980px; margin: 14px 0 20px; font-size: clamp(42px, 7vw, 82px); line-height: 1.05; }
.internal-hero p { max-width: 760px; margin-bottom: 26px; font-size: 17px; }
.guide-hero { background: linear-gradient(90deg, var(--paper) 0 72%, var(--yellow) 72%); }
.faq-hero { color: var(--white); background: linear-gradient(90deg, var(--green-dark) 0 74%, var(--red) 74%); }
.faq-hero .eyebrow { color: var(--yellow); }

.guide-layout { display: grid; grid-template-columns: 260px minmax(0, 1fr); align-items: start; gap: clamp(42px, 7vw, 110px); max-width: 1450px; margin: 0 auto; }
.guide-index { position: sticky; top: 102px; display: flex; flex-direction: column; border: 1px solid var(--ink); background: var(--white); }
.guide-index span { padding: 15px 18px; color: var(--white); background: var(--red); font-size: 11px; font-weight: 900; }
.guide-index a { padding: 13px 18px; border-bottom: 1px solid var(--line); font-size: 13px; font-weight: 700; }
.guide-index a:last-child { border-bottom: 0; }
.guide-index a:hover { background: var(--yellow); }
.guide-chapters article { padding: 0 0 58px; margin-bottom: 58px; border-bottom: 1px solid var(--ink); }
.guide-chapters article:last-child { margin-bottom: 0; }
.chapter-code { display: block; margin-bottom: 12px; color: var(--red); font-size: 11px; font-weight: 900; }
.guide-chapters h2 { font-size: clamp(29px, 4vw, 46px); }
.guide-chapters p { max-width: 900px; color: #3f3d38; font-size: 16px; line-height: 2; }
.guide-chapters a { color: var(--red-dark); font-weight: 800; border-bottom: 1px solid var(--red); }
code { padding: 2px 6px; color: var(--red-dark); background: #ece8de; }
.check-line { display: grid; grid-template-columns: 140px 1fr; gap: 18px; padding: 20px; border-left: 6px solid var(--green); background: #e8f0ea; }

.faq-section { max-width: 1250px; margin: 0 auto; }
.faq-toolbar { display: flex; justify-content: space-between; align-items: center; padding-bottom: 16px; border-bottom: 2px solid var(--ink); font-size: 12px; font-weight: 900; }
.faq-toolbar button { padding: 8px 14px; border: 1px solid var(--ink); background: var(--yellow); cursor: pointer; font-weight: 800; }
.faq-item { border-bottom: 1px solid var(--ink); }
.faq-item h2 { margin: 0; font-size: 18px; }
.faq-item h2 button { width: 100%; min-height: 84px; display: grid; grid-template-columns: 52px 1fr 30px; align-items: center; gap: 20px; padding: 18px 0; border: 0; color: var(--ink); background: transparent; text-align: left; cursor: pointer; }
.faq-item h2 button span { color: var(--red); font-size: 12px; font-weight: 900; }
.faq-item h2 button b { justify-self: end; width: 28px; height: 28px; display: grid; place-items: center; color: var(--white); background: var(--green); }
.faq-answer { padding: 0 50px 28px 72px; }
.faq-answer p { max-width: 930px; margin: 0; color: var(--muted); line-height: 2; }
.faq-item.is-open { background: var(--white); }
.faq-afterword { margin-top: 72px; padding: 32px; color: var(--white); background: var(--green-dark); }
.faq-afterword h2 { margin-bottom: 12px; }
.faq-afterword p { margin: 0; }
.faq-afterword a { color: var(--yellow); font-weight: 900; }

@media (max-width: 980px) {
  .site-header { min-height: 64px; }
  .header-inner { min-height: 63px; padding: 10px 20px; }
  .menu-button { display: grid; place-items: center; }
  .site-nav { position: fixed; top: 64px; left: 0; right: 0; display: none; flex-direction: column; align-items: stretch; gap: 0; padding: 12px 20px 20px; background: var(--paper); border-bottom: 1px solid var(--ink); }
  .site-nav.is-open { display: flex; }
  .site-nav a { padding: 12px 4px; border-bottom: 1px solid var(--line); }
  .site-nav .nav-download { margin-top: 12px; border: 0; text-align: center; }
  .hero { width: calc(100% - 32px); min-height: 590px; grid-template-columns: 56% 44%; }
  .hero-device { min-height: 590px; padding: 26px 18px 62px; }
  .hero-device img { width: min(72%, 225px); }
  .hero-copy { padding: 44px 34px 68px; }
  .hero h1 { font-size: clamp(46px, 7.5vw, 68px); }
  .hero-copy > p { font-size: 15px; }
  .creator-row { grid-template-columns: 1fr 1fr; }
  .creator-entry:nth-child(2) { border-right: 0; }
  .creator-entry:nth-child(-n+2) { border-bottom: 1px solid var(--ink); }
  .gallery-strip { gap: 20px; }
  .image-mount { min-height: 480px; padding: 18px; }
  .link-shelves a { grid-template-columns: 140px 1fr; }
  .link-shelves small { grid-column: 2; }
}

@media (max-width: 680px) {
  html { scroll-padding-top: 72px; }
  .header-inner { padding: 10px 16px; }
  .brand img { width: 38px; height: 38px; }
  .hero { width: 100%; min-height: 0; grid-template-columns: 1fr; border-right: 0; border-left: 0; }
  .hero-copy { padding: 30px 22px 26px; background-size: 42px 100%; text-align: center; }
  .hero h1 { max-width: 440px; margin: 10px auto 14px; font-size: clamp(42px, 13vw, 58px); line-height: 1; }
  .hero-copy > p { max-width: 520px; margin: 0 auto 18px; font-size: 14px; line-height: 1.75; }
  .hero-actions { justify-content: center; gap: 16px; }
  .button { min-height: 42px; padding: 9px 18px; }
  .text-link { font-size: 12px; }
  .alphabet-rail { width: 100%; max-width: 430px; grid-template-columns: repeat(10, 1fr); margin: 18px auto 0; }
  .alphabet-rail span { min-height: 30px; font-size: 11px; border-bottom: 1px solid var(--ink); }
  .alphabet-rail span { border-bottom: 0; }
  .hero-device { min-height: 250px; padding: 20px 16px 54px; border-top: 1px solid var(--ink); border-left: 0; }
  .hero-device::before { inset: 10px 12px 50px; }
  .hero-device img { width: min(31%, 116px); filter: drop-shadow(7px 8px 0 rgba(24,24,23,.3)); }
  .device-label { top: 18px; left: 22px; font-size: 9px; }
  .next-shelf { height: 42px; padding: 0 10px; font-size: 10px; text-align: center; }
  .section-band { padding: 58px 18px; }
  .section-heading { grid-template-columns: 44px 1fr; gap: 12px; margin-bottom: 30px; }
  .section-number { width: 38px; height: 38px; }
  .section-heading h2 { font-size: 32px; }
  .section-note { grid-column: 2; justify-self: start; text-align: left; }
  .creator-row, .feature-list, .gallery-strip { grid-template-columns: 1fr; }
  .creator-entry { min-height: 230px; border-right: 0; border-bottom: 1px solid var(--ink); }
  .creator-entry:last-child { border-bottom: 0; }
  .creator-letter { font-size: 64px; }
  .creator-entry h3 { margin-top: 18px; }
  .feature-list article, .feature-list article:nth-child(2n), .feature-list article:nth-last-child(-n+2) { min-height: 220px; border-right: 0; border-bottom: 1px solid var(--ink); }
  .feature-list article:last-child { border-bottom: 0; }
  .feature-list h3 { margin-top: 34px; }
  .gallery-strip { max-width: 340px; }
  .image-mount { min-height: 0; padding: 20px; }
  .image-mount img { width: min(100%, 300px); }
  .route-list li { grid-template-columns: 34px 1fr; gap: 10px; }
  .route-list p { grid-column: 2; }
  .link-shelves a { grid-template-columns: 1fr; gap: 8px; }
  .link-shelves small { grid-column: 1; }
  .download-band { align-items: flex-start; flex-direction: column; padding: 44px 18px; }
  .site-footer nav { flex-wrap: wrap; }
  .internal-hero { min-height: 430px; padding: 60px 18px; }
  .internal-hero h1 { font-size: 42px; }
  .guide-hero { background: linear-gradient(180deg, var(--paper) 0 88%, var(--yellow) 88%); }
  .faq-hero { background: linear-gradient(180deg, var(--green-dark) 0 90%, var(--red) 90%); }
  .guide-layout { grid-template-columns: 1fr; }
  .guide-index { position: static; }
  .guide-chapters article { scroll-margin-top: 74px; }
  .check-line { grid-template-columns: 1fr; }
  .faq-item h2 { font-size: 16px; }
  .faq-item h2 button { grid-template-columns: 34px 1fr 28px; gap: 10px; }
  .faq-answer { padding: 0 12px 24px 44px; }
  .faq-afterword { padding: 24px 20px; }
}

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