:root {
  color-scheme: light dark;
  --background: #f7f7f5;
  --text: #1c1c1a;
  --muted: #6b6b66;
  --line: #e2e2dd;
  --link: #42423d;
  --surface: #ffffff;
  --soft-surface: #f0f3ef;
  --accent: #4f7953;
  --accent-soft: #e6efe5;
  --max-width: 43rem;
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "SF Pro Display", "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --background: #111110;
    --text: #ecece8;
    --muted: #9a9a94;
    --line: #2d2d29;
    --link: #f0f0eb;
    --surface: #1a1a18;
    --soft-surface: #20241f;
    --accent: #91ba92;
    --accent-soft: #243226;
  }
}

* {
  box-sizing: border-box;
}

html {
  font-size: 17px;
  -webkit-text-size-adjust: 100%;
}

body {
  min-width: 320px;
  margin: 0;
  color: var(--text);
  background: var(--background);
  font-size: 1rem;
  line-height: 1.72;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.language-control {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.page-shell {
  width: min(var(--max-width), calc(100% - 2.5rem));
  margin: 0 auto;
  padding: 1.75rem 0 3.5rem;
}

.site-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  padding-bottom: 1.15rem;
  border-bottom: 1px solid var(--line);
}

.site-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  margin-left: auto;
  font-size: 0.86rem;
}

.site-nav a {
  color: var(--muted);
  text-decoration: none;
}

.site-nav a:hover,
.site-nav a[aria-current="page"] {
  color: var(--text);
}

.site-nav a[aria-current="page"] {
  font-weight: 650;
}

.nav-en {
  display: none;
}

.brand {
  color: var(--text);
  font-size: 0.96rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  text-decoration: none;
}

.brand span {
  color: var(--muted);
  font-weight: 400;
}

.language-switch {
  color: var(--muted);
  font-size: 0.88rem;
  white-space: nowrap;
}

.language-switch label {
  cursor: pointer;
  color: var(--muted);
}

.language-switch label:hover {
  color: var(--text);
}

.language-switch label:focus-visible {
  outline: 2px solid var(--text);
  outline-offset: 3px;
  border-radius: 2px;
}

.language-switch span {
  margin: 0 0.45em;
  color: var(--line);
}

#language-zh:checked ~ .page-shell .language-switch label[for="language-zh"],
#language-en:checked ~ .page-shell .language-switch label[for="language-en"] {
  color: var(--text);
  font-weight: 600;
}

#language-zh:checked ~ .page-shell .policy-en,
#language-en:checked ~ .page-shell .policy-zh,
#language-zh:checked ~ .page-shell .manual-en,
#language-en:checked ~ .page-shell .manual-zh,
#language-en:checked ~ .page-shell .nav-zh,
#language-zh:checked ~ .page-shell .nav-en {
  display: none;
}

#language-en:checked ~ .page-shell .nav-en {
  display: inline;
}

main {
  padding-top: 2.15rem;
}

.policy > :first-child {
  margin-top: 0;
}

h1,
h2,
h3 {
  color: var(--text);
  line-height: 1.35;
  font-weight: 650;
  letter-spacing: -0.015em;
}

h1 {
  margin: 0 0 1.1rem;
  font-size: 1.72rem;
}

h2 {
  margin: 2rem 0 0.68rem;
  font-size: 1.16rem;
}

h3 {
  margin: 1.42rem 0 0.48rem;
  font-size: 1.01rem;
}

p,
ul,
ol {
  margin: 0 0 1rem;
}

ul,
ol {
  padding-left: 1.3rem;
}

li + li {
  margin-top: 0.34rem;
}

a {
  color: var(--link);
  text-underline-offset: 0.15em;
}

a:hover {
  color: var(--muted);
}

.updated {
  color: var(--muted);
  font-size: 0.9rem;
}

hr {
  height: 0;
  margin: 2rem 0;
  border: 0;
  border-top: 1px solid var(--line);
}

footer {
  margin-top: 3.1rem;
  padding-top: 1.15rem;
  color: var(--muted);
  border-top: 1px solid var(--line);
  font-size: 0.84rem;
}

footer a {
  margin-left: 0.75rem;
}

/* Detailed user guide */
.guide-shell {
  --max-width: 76rem;
}

.guide-main {
  padding-top: 2.4rem;
}

.manual {
  display: grid;
  grid-template-columns: minmax(12rem, 16rem) minmax(0, 1fr);
  column-gap: clamp(2.5rem, 6vw, 5.5rem);
}

.manual-hero {
  grid-column: 1 / -1;
  max-width: 54rem;
  margin-bottom: 3rem;
}

.manual-kicker {
  margin-bottom: 0.35rem;
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 750;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.manual-hero h1 {
  margin-bottom: 0.8rem;
  font-size: clamp(2rem, 4vw, 3.45rem);
  letter-spacing: -0.035em;
}

.manual-lead {
  max-width: 45rem;
  color: var(--muted);
  font-size: 1.08rem;
}

.manual-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1rem;
  margin: 1.35rem 0 1.5rem;
  color: var(--muted);
  font-size: 0.82rem;
}

.manual-meta span + span::before {
  margin-right: 1rem;
  color: var(--line);
  content: "•";
}

.notice-card,
.tip {
  border: 1px solid color-mix(in srgb, var(--accent) 22%, var(--line));
  border-radius: 1rem;
  background: var(--accent-soft);
}

.notice-card {
  max-width: 48rem;
  padding: 1.1rem 1.25rem;
}

.notice-card strong {
  display: block;
  margin-bottom: 0.2rem;
}

.notice-card p,
.tip span {
  margin: 0;
  color: var(--muted);
}

.notice-card.compact {
  margin-top: 1.25rem;
}

.manual-toc {
  grid-column: 1;
  grid-row: 2 / span 20;
  align-self: start;
  position: sticky;
  top: 1.5rem;
  padding: 1.15rem 1.1rem;
  border: 1px solid var(--line);
  border-radius: 1rem;
  background: var(--surface);
  box-shadow: 0 0.8rem 2.2rem rgb(0 0 0 / 0.035);
}

.manual-toc > strong {
  display: block;
  margin-bottom: 0.6rem;
  font-size: 0.88rem;
}

.manual-toc ol {
  margin: 0;
  padding-left: 1.25rem;
  color: var(--muted);
  font-size: 0.78rem;
  line-height: 1.48;
}

.manual-toc li + li {
  margin-top: 0.32rem;
}

.manual-toc a {
  color: inherit;
  text-decoration: none;
}

.manual-toc a:hover {
  color: var(--accent);
}

.manual-section {
  grid-column: 2;
  min-width: 0;
  padding: 0 0 3.25rem;
  scroll-margin-top: 1.5rem;
}

.manual-section + .manual-section {
  padding-top: 3rem;
  border-top: 1px solid var(--line);
}

.section-number {
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 750;
  letter-spacing: 0.13em;
}

.manual-section h2 {
  margin-top: 0.25rem;
  font-size: 1.7rem;
  letter-spacing: -0.025em;
}

.manual-section h3 {
  margin-top: 1.8rem;
  font-size: 1.05rem;
}

.path {
  display: flex;
  align-items: baseline;
  gap: 0.65rem;
  padding: 0.78rem 0.9rem;
  border-radius: 0.75rem;
  background: var(--soft-surface);
  font-size: 0.9rem;
}

.path span {
  flex: none;
  color: var(--accent);
  font-size: 0.72rem;
  font-weight: 750;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.steps {
  counter-reset: manual-step;
  padding-left: 0;
  list-style: none;
}

.steps li {
  position: relative;
  padding-left: 2.35rem;
  counter-increment: manual-step;
}

.steps li::before {
  position: absolute;
  top: 0.08rem;
  left: 0;
  display: grid;
  width: 1.55rem;
  height: 1.55rem;
  place-items: center;
  border-radius: 50%;
  color: var(--accent);
  background: var(--accent-soft);
  content: counter(manual-step);
  font-size: 0.72rem;
  font-weight: 750;
}

.steps li + li {
  margin-top: 0.78rem;
}

.tip {
  display: grid;
  grid-template-columns: max-content minmax(0, 1fr);
  gap: 0.85rem;
  margin: 1.35rem 0;
  padding: 1rem 1.1rem;
  font-size: 0.9rem;
}

.tip b {
  color: var(--accent);
}

.route-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.7rem;
}

.route-grid.two-column {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.route-grid > div {
  display: flex;
  min-height: 7.2rem;
  flex-direction: column;
  gap: 0.35rem;
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: 0.9rem;
  background: var(--surface);
}

.route-grid b {
  font-size: 0.94rem;
}

.route-grid span {
  color: var(--muted);
  font-size: 0.82rem;
  line-height: 1.5;
}

.manual-section details {
  border-bottom: 1px solid var(--line);
}

.manual-section details:first-of-type {
  border-top: 1px solid var(--line);
}

.manual-section summary {
  padding: 1rem 0;
  cursor: pointer;
  font-weight: 650;
}

.manual-section details p {
  padding: 0 1.25rem 1rem 0;
  color: var(--muted);
}

@media (min-width: 640px) {
  html {
    font-size: 18px;
  }

  .page-shell {
    padding-top: 2.4rem;
    padding-bottom: 4.5rem;
  }
}

@media (max-width: 420px) {
  .page-shell {
    width: min(var(--max-width), calc(100% - 2rem));
  }

  .site-header {
    align-items: flex-start;
  }
}

@media (max-width: 860px) {
  .site-header {
    flex-wrap: wrap;
  }

  .site-nav {
    order: 3;
    width: 100%;
    justify-content: flex-start;
    padding-top: 0.7rem;
    border-top: 1px solid var(--line);
  }

  .manual {
    display: block;
  }

  .manual-hero {
    margin-bottom: 1.5rem;
  }

  .manual-toc {
    position: static;
    margin-bottom: 2.6rem;
  }

  .manual-toc ol {
    columns: 2;
    column-gap: 2rem;
  }

  .manual-toc li {
    break-inside: avoid;
  }
}

@media (max-width: 580px) {
  .guide-main {
    padding-top: 1.75rem;
  }

  .manual-toc ol {
    columns: 1;
  }

  .manual-meta {
    display: grid;
  }

  .manual-meta span + span::before {
    content: none;
  }

  .route-grid,
  .route-grid.two-column {
    grid-template-columns: 1fr;
  }

  .route-grid > div {
    min-height: 0;
  }

  .tip {
    grid-template-columns: 1fr;
    gap: 0.2rem;
  }

  .path {
    align-items: flex-start;
  }
}

@media print {
  :root {
    color-scheme: light;
    --background: #fff;
    --text: #000;
    --muted: #555;
    --line: #ccc;
    --link: #000;
  }

  .page-shell {
    width: 100%;
    padding: 0;
  }

  .language-switch {
    display: none;
  }

  .site-nav,
  .manual-toc {
    display: none;
  }

  .manual {
    display: block;
  }

  .policy-en {
    display: none !important;
  }

  a {
    color: inherit;
  }
}