:root {
  --paper: #f4efe6;
  --paper-deep: #e9decf;
  --ink: #26231f;
  --muted: #73685d;
  --line: #d4c7b8;
  --panel: #fffaf2;
  --accent: #235b63;
  --accent-strong: #173f45;
  --rust: #a34d33;
  --sage: #6d7d53;
  --shadow: 0 18px 48px rgba(64, 47, 33, .14);
  --shadow-strong: 0 24px 62px rgba(35, 91, 99, .2);
  --focus-ring: 0 0 0 4px rgba(35, 91, 99, .16);
  --radius: 8px;
  --sidebar: 286px;
  --max: 1220px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  background: var(--paper);
}

body {
  margin: 0;
  min-width: 320px;
  color: var(--ink);
  background:
    linear-gradient(90deg, rgba(35, 91, 99, .06) 1px, transparent 1px),
    linear-gradient(0deg, rgba(35, 91, 99, .045) 1px, transparent 1px),
    var(--paper);
  background-size: 42px 42px;
  font-family: "Noto Sans SC", "Microsoft YaHei", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.75;
  letter-spacing: 0;
  text-rendering: optimizeLegibility;
}

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

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

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

a:focus-visible,
button:focus-visible,
summary:focus-visible {
  outline: 0;
  box-shadow: var(--focus-ring);
}

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

strong,
b {
  color: var(--accent-strong);
  font-weight: 800;
}

h1,
h2,
h3 {
  margin: 0;
  color: var(--accent-strong);
  line-height: 1.18;
  letter-spacing: 0;
}

h1 {
  max-width: 760px;
  color: var(--accent-strong);
  font-size: clamp(2.08rem, 4.4vw, 4.35rem);
  text-shadow: 0 2px 0 rgba(163, 77, 51, .16);
}

h2 {
  color: var(--accent);
  font-size: clamp(1.28rem, 2.1vw, 2.08rem);
}

h3 {
  font-size: clamp(1.05rem, 1.5vw, 1.28rem);
}

ul {
  margin: 0;
  padding: 0;
}

li {
  list-style: none;
}

.skip-link {
  position: fixed;
  left: 16px;
  top: 12px;
  z-index: 1000;
  transform: translateY(-150%);
  padding: 9px 13px;
  border: 1px solid var(--accent);
  border-radius: 4px;
  background: var(--panel);
  color: var(--accent-strong);
  font-weight: 800;
}

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

.topbar {
  display: none;
}

.page-shell {
  width: min(100%, var(--max));
  margin: 0 auto;
  display: grid;
  grid-template-columns: var(--sidebar) minmax(0, 1fr);
  gap: 28px;
  padding: 28px 22px 52px;
}

.sidebar {
  position: sticky;
  top: 28px;
  align-self: start;
  min-height: calc(100vh - 56px);
  display: flex;
  flex-direction: column;
  gap: 24px;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(255, 250, 242, .88);
  box-shadow: var(--shadow);
  backdrop-filter: blur(12px);
  transition: box-shadow .28s ease, border-color .28s ease, transform .28s ease;
}

.sidebar:hover {
  border-color: rgba(35, 91, 99, .34);
  box-shadow: var(--shadow-strong);
}

.sidebar-brand {
  display: grid;
  gap: 12px;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--line);
  font-weight: 900;
  color: var(--accent-strong);
  transition: color .24s ease;
}

.sidebar-brand:hover {
  color: var(--rust);
}

.sidebar-brand img {
  width: 74px;
  aspect-ratio: 1;
  object-fit: contain;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #fdf8ef;
  transition: transform .28s ease, border-color .28s ease, box-shadow .28s ease;
}

.sidebar-brand:hover img {
  transform: translateY(-2px) scale(1.04);
  border-color: rgba(163, 77, 51, .45);
  box-shadow: 0 12px 28px rgba(64, 47, 33, .16);
}

.toc {
  display: grid;
  gap: 8px;
}

.toc a {
  display: grid;
  grid-template-columns: 42px 1fr;
  align-items: center;
  gap: 12px;
  padding: 11px 10px;
  border: 1px solid transparent;
  border-radius: 6px;
  color: var(--muted);
  font-weight: 800;
  transition: background .2s ease, border-color .2s ease, color .2s ease, transform .2s ease;
}

.toc a:hover,
.toc a:focus-visible,
.toc a.is-active {
  border-color: rgba(35, 91, 99, .32);
  background: linear-gradient(135deg, #edf5f1, #fff8ee);
  color: var(--accent-strong);
  transform: translateX(5px);
  box-shadow: 0 10px 24px rgba(35, 91, 99, .1);
}

.toc span {
  color: var(--rust);
  font-size: .78rem;
}

.download-chip {
  margin-top: auto;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 10px 14px;
  border-radius: 6px;
  background: var(--accent);
  color: #fff;
  font-weight: 900;
  box-shadow: 0 12px 28px rgba(35, 91, 99, .22);
  transition: transform .22s ease, box-shadow .22s ease, background .22s ease;
}

.download-chip:hover,
.download-chip:focus-visible {
  background: var(--accent-strong);
  transform: translateY(-3px);
  box-shadow: 0 18px 36px rgba(35, 91, 99, .3);
}

.content-flow {
  min-width: 0;
  display: grid;
  gap: 22px;
}

.hero,
.section,
.stat-strip {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(255, 250, 242, .92);
  box-shadow: var(--shadow);
  transition: border-color .28s ease, box-shadow .28s ease, transform .28s ease;
}

.hero:hover,
.section:hover,
.stat-strip:hover {
  border-color: rgba(35, 91, 99, .3);
  box-shadow: var(--shadow-strong);
}

.hero {
  min-height: min(720px, calc(100vh - 56px));
  display: grid;
  grid-template-columns: minmax(0, 1.04fr) minmax(280px, .82fr);
  gap: 24px;
  align-items: stretch;
  padding: clamp(22px, 4vw, 44px);
}

.hero-copy {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 22px;
  min-width: 0;
}

.kicker {
  color: var(--rust);
  font-size: .78rem;
  font-weight: 900;
  letter-spacing: 0;
  text-transform: uppercase;
}

.hero-lead {
  max-width: 680px;
  color: #5f554c;
  font-size: clamp(1rem, 1.55vw, 1.18rem);
}

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

.primary-action,
.secondary-action {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 11px 18px;
  border-radius: 6px;
  font-weight: 900;
  position: relative;
  overflow: hidden;
  transition: transform .22s ease, box-shadow .22s ease, border-color .22s ease, background .22s ease, color .22s ease;
}

.primary-action::after,
.secondary-action::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(120deg, transparent 0%, rgba(255, 255, 255, .28) 45%, transparent 70%);
  transform: translateX(-120%);
  transition: transform .48s ease;
}

.primary-action:hover,
.secondary-action:hover,
.primary-action:focus-visible,
.secondary-action:focus-visible {
  transform: translateY(-3px);
}

.primary-action:hover,
.primary-action:focus-visible {
  background: var(--accent-strong);
  box-shadow: 0 16px 34px rgba(35, 91, 99, .28);
}

.secondary-action:hover,
.secondary-action:focus-visible {
  border-color: rgba(35, 91, 99, .38);
  background: #edf5f1;
  box-shadow: 0 14px 30px rgba(64, 47, 33, .12);
}

.primary-action:hover::after,
.secondary-action:hover::after,
.primary-action:focus-visible::after,
.secondary-action:focus-visible::after {
  transform: translateX(120%);
}

.primary-action {
  background: var(--accent);
  color: #fff;
}

.secondary-action {
  border: 1px solid var(--line);
  background: #fffaf2;
  color: var(--accent-strong);
}

.hero-visual {
  position: relative;
  margin: 0;
  min-height: 100%;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper-deep);
  transition: transform .32s ease, box-shadow .32s ease, border-color .32s ease;
}

.hero-visual:hover {
  transform: translateY(-4px);
  border-color: rgba(163, 77, 51, .42);
  box-shadow: 0 22px 46px rgba(64, 47, 33, .18);
}

.hero-visual img {
  width: 100%;
  height: 100%;
  min-height: 420px;
  object-fit: contain;
  padding: clamp(10px, 1.8vw, 18px);
  transition: transform .42s ease, filter .42s ease;
}

.hero-visual:hover img {
  transform: scale(1.025);
  filter: saturate(1.06) contrast(1.03);
}

.hero-visual figcaption {
  position: absolute;
  left: 14px;
  bottom: 14px;
  padding: 7px 10px;
  border-radius: 4px;
  background: rgba(255, 250, 242, .9);
  color: var(--accent-strong);
  font-size: .82rem;
  font-weight: 800;
}

.stat-strip {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  overflow: hidden;
}

.stat-strip div {
  min-width: 0;
  padding: 18px 20px;
  border-right: 1px solid var(--line);
  transition: background .22s ease, transform .22s ease;
}

.stat-strip div:hover {
  background: #edf5f1;
  transform: translateY(-2px);
}

.stat-strip div:last-child {
  border-right: 0;
}

.stat-strip span {
  display: block;
  color: var(--muted);
  font-size: .82rem;
  font-weight: 800;
}

.stat-strip strong {
  display: block;
  margin-top: 4px;
  color: var(--ink);
  font-size: clamp(1rem, 1.5vw, 1.24rem);
}

.section {
  padding: clamp(22px, 3.6vw, 36px);
  scroll-margin-top: 28px;
}

.section-title {
  display: grid;
  gap: 8px;
  margin-bottom: 22px;
}

.dossier-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.brief-card,
.route-step,
.feature-grid article,
.timeline article,
.faq-list details {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fffdf8;
  transition: transform .24s ease, box-shadow .24s ease, border-color .24s ease, background .24s ease;
}

.brief-card:hover,
.route-step:hover,
.feature-grid article:hover,
.timeline article:hover,
.faq-list details:hover {
  border-color: rgba(35, 91, 99, .34);
  background: #fffaf2;
  box-shadow: 0 16px 34px rgba(64, 47, 33, .12);
  transform: translateY(-4px);
}

.brief-card {
  min-height: 218px;
  padding: 20px;
}

.brief-card h3,
.route-step h3,
.feature-grid h3,
.brief-card h3,
.route-step h3,
.feature-grid h3 {
  margin-bottom: 10px;
}

.story-board {
  display: grid;
  grid-template-columns: minmax(260px, .92fr) minmax(0, 1fr);
  gap: 20px;
  align-items: center;
}

.story-board figure {
  margin: 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper-deep);
  transition: transform .28s ease, box-shadow .28s ease, border-color .28s ease;
}

.story-board figure:hover {
  transform: translateY(-4px);
  border-color: rgba(35, 91, 99, .34);
  box-shadow: 0 16px 34px rgba(64, 47, 33, .13);
}

.story-board img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: contain;
  background: var(--paper-deep);
  transition: transform .36s ease, filter .36s ease;
}

.story-board figure:hover img {
  transform: scale(1.025);
  filter: saturate(1.05) contrast(1.02);
}

.story-copy {
  display: grid;
  gap: 14px;
}

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

.plain-list li {
  padding: 12px 14px;
  border-left: 4px solid var(--sage);
  background: #f7f4ed;
  color: var(--muted);
  transition: border-color .22s ease, background .22s ease, transform .22s ease;
}

.plain-list li:hover {
  border-left-color: var(--rust);
  background: #fff8ee;
  transform: translateX(4px);
}

.route-layout {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.route-step {
  padding: 20px;
}

.route-step span {
  display: inline-block;
  margin-bottom: 12px;
  color: var(--rust);
  font-size: .8rem;
  font-weight: 900;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.feature-grid article {
  overflow: hidden;
}

.feature-grid article:hover h3 {
  color: var(--rust);
}

.feature-grid img {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: contain;
  background: var(--paper-deep);
  border-bottom: 1px solid var(--line);
  transition: transform .36s ease, filter .36s ease;
}

.feature-grid article:hover img {
  transform: scale(1.03);
  filter: saturate(1.07) contrast(1.03);
}

.feature-grid h3,
.feature-grid p {
  padding-left: 18px;
  padding-right: 18px;
}

.feature-grid h3 {
  padding-top: 16px;
}

.feature-grid p {
  padding-bottom: 18px;
}

.timeline {
  position: relative;
  display: grid;
  gap: 10px;
}

.timeline article {
  display: grid;
  grid-template-columns: 118px 156px minmax(0, 1fr);
  align-items: center;
  gap: 14px;
  padding: 13px 16px;
}

.timeline time {
  color: var(--rust);
  font-size: .82rem;
  font-weight: 900;
}

.timeline h3 {
  margin: 0;
  color: var(--accent-strong);
  font-size: .96rem;
  line-height: 1.35;
}

.timeline p {
  color: #62584f;
  font-size: .9rem;
  line-height: 1.58;
}

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

.faq-list details {
  padding: 16px 18px;
}

.faq-list details[open] {
  border-color: rgba(35, 91, 99, .36);
  background: linear-gradient(180deg, #fffdf8, #edf5f1);
}

.faq-list summary {
  cursor: pointer;
  color: var(--ink);
  font-weight: 900;
  border-radius: 4px;
  transition: color .2s ease;
}

.faq-list summary:hover {
  color: var(--accent);
}

.faq-list p {
  margin-top: 10px;
}

.site-footer {
  width: min(100%, var(--max));
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 0 22px 34px calc(var(--sidebar) + 50px);
  color: var(--muted);
}

.friend-links {
  margin-top: 10px;
  background:
    radial-gradient(circle at 50% 36%, rgba(233, 222, 207, .14), transparent 25%),
    linear-gradient(90deg, var(--accent-strong), var(--accent), var(--accent-strong));
  color: #fff;
}

.friend-links-inner {
  width: min(100%, var(--max));
  margin: 0 auto;
  padding: 54px 22px 58px calc(var(--sidebar) + 50px);
  text-align: center;
}

.friend-links h2 {
  margin-bottom: 18px;
  color: #ead7a8;
  font-size: clamp(1.55rem, 2.4vw, 2.35rem);
  font-weight: 900;
  text-shadow: 0 8px 28px rgba(0, 0, 0, .22);
}

.friend-link-list {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
}

.friend-link-list a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 10px 22px;
  border: 1px solid rgba(255, 250, 242, .58);
  border-radius: 999px;
  background: #fff8e8;
  color: #133b35;
  font-weight: 900;
  box-shadow: 0 12px 26px rgba(0, 0, 0, .14);
  transition: transform .22s ease, box-shadow .22s ease, background .22s ease, color .22s ease, border-color .22s ease;
}

.friend-link-list a:hover,
.friend-link-list a:focus-visible {
  transform: translateY(-4px);
  border-color: #ead7a8;
  background: #ead7a8;
  color: var(--accent-strong);
  box-shadow: 0 18px 36px rgba(0, 0, 0, .22);
}

.site-footer a {
  color: var(--accent-strong);
  font-weight: 900;
  transition: color .2s ease, transform .2s ease;
}

.site-footer a:hover,
.site-footer a:focus-visible {
  color: var(--rust);
  transform: translateY(-2px);
}

.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity .5s ease, transform .5s ease;
}

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

@media (max-width: 980px) {
  .topbar {
    position: sticky;
    top: 0;
    z-index: 100;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 14px;
    padding: 10px 16px;
    border-bottom: 1px solid var(--line);
    background: rgba(255, 250, 242, .94);
    backdrop-filter: blur(12px);
  }

  .site-mark {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    min-width: 0;
    transition: transform .22s ease;
  }

  .site-mark:hover,
  .site-mark:focus-visible {
    transform: translateY(-2px);
  }

  .site-mark img {
    width: 38px;
    height: 38px;
    object-fit: contain;
    border: 1px solid var(--line);
    border-radius: 5px;
    transition: border-color .22s ease, box-shadow .22s ease;
  }

  .site-mark:hover img,
  .site-mark:focus-visible img {
    border-color: rgba(35, 91, 99, .38);
    box-shadow: 0 8px 18px rgba(64, 47, 33, .14);
  }

  .site-mark span {
    display: grid;
    min-width: 0;
    line-height: 1.12;
  }

  .site-mark b {
    color: var(--ink);
  }

  .site-mark small {
    color: var(--muted);
    font-weight: 800;
  }

  .menu-button {
    width: 42px;
    height: 42px;
    display: grid;
    place-content: center;
    gap: 5px;
    border: 1px solid var(--line);
    border-radius: 6px;
    background: #fffaf2;
    transition: border-color .22s ease, background .22s ease, transform .22s ease, box-shadow .22s ease;
  }

  .menu-button:hover,
  .menu-button:focus-visible {
    border-color: rgba(35, 91, 99, .38);
    background: #edf5f1;
    transform: translateY(-2px);
    box-shadow: 0 10px 22px rgba(64, 47, 33, .12);
  }

  .menu-button span {
    width: 18px;
    height: 2px;
    background: var(--accent-strong);
    transition: transform .2s ease, opacity .2s ease;
  }

  .menu-button.is-open span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }

  .menu-button.is-open span:nth-child(2) {
    opacity: 0;
  }

  .menu-button.is-open span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }

  .quick-nav {
    position: absolute;
    left: 12px;
    right: 12px;
    top: calc(100% + 8px);
    display: none;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 8px;
    padding: 12px;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: #fffaf2;
    box-shadow: var(--shadow);
  }

  .quick-nav.is-open {
    display: grid;
  }

  .quick-nav a {
    padding: 10px;
    border: 1px solid var(--line);
    border-radius: 6px;
    color: var(--accent-strong);
    font-weight: 900;
    text-align: center;
    transition: background .2s ease, border-color .2s ease, color .2s ease, transform .2s ease;
  }

  .quick-nav a:hover,
  .quick-nav a:focus-visible {
    border-color: rgba(35, 91, 99, .38);
    background: #edf5f1;
    color: var(--rust);
    transform: translateY(-2px);
  }

  .page-shell {
    display: block;
    padding: 18px 14px 42px;
  }

  .sidebar {
    display: none;
  }

  .content-flow {
    gap: 16px;
  }

  .hero {
    min-height: auto;
    grid-template-columns: 1fr;
  }

  .hero-visual {
    order: -1;
  }

  .hero-visual img {
    min-height: 0;
    aspect-ratio: 16 / 11;
  }

  .site-footer {
    padding: 0 14px 28px;
  }

  .friend-links-inner {
    padding: 42px 14px 46px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: .01ms !important;
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
  }
}

@media (max-width: 760px) {
  h1 {
    font-size: clamp(1.9rem, 9.5vw, 2.72rem);
  }

  .hero,
  .section {
    padding: 18px;
  }

  .stat-strip,
  .dossier-grid,
  .story-board,
  .route-layout,
  .feature-grid,
  .timeline article {
    grid-template-columns: 1fr;
  }

  .timeline article {
    gap: 6px;
    padding: 14px;
  }

  .timeline h3 {
    font-size: .98rem;
  }

  .timeline p {
    font-size: .9rem;
    line-height: 1.62;
  }

  .stat-strip div {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .stat-strip div:last-child {
    border-bottom: 0;
  }

  .brief-card {
    min-height: 0;
  }

  .hero-actions {
    display: grid;
  }

  .primary-action,
  .secondary-action {
    width: 100%;
  }

  .site-footer {
    display: grid;
  }

  .friend-link-list {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 10px;
  }

  .friend-link-list a {
    min-width: 0;
    padding: 10px 12px;
    font-size: .92rem;
  }
}