:root {
  --ink: #14202b;
  --muted: #5f6f7c;
  --soft: #f3f7f9;
  --line: #dce6e9;
  --green: #1e7b4d;
  --green-dark: #0a2e24;
  --blue: #1264ff;
  --orange: #ff7a1a;
  --lime: #b8f21d;
  --danger: #c53b47;
  --white: #fff;
  --shadow: 0 20px 50px rgba(18, 37, 49, .12);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 96px; }
body { margin: 0; color: var(--ink); background: var(--white); font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif; line-height: 1.75; }
img { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
p, h1, h2, h3, h4 { margin-top: 0; }

.skip-link { position: fixed; z-index: 100; top: -60px; left: 16px; padding: 10px 14px; color: var(--ink); background: var(--lime); border-radius: 8px; }
.skip-link:focus { top: 10px; }

.help-header { position: sticky; z-index: 20; top: 0; height: 72px; display: flex; align-items: center; justify-content: space-between; gap: 24px; padding: 0 40px; color: var(--white); background: rgba(6, 24, 29, .96); border-bottom: 1px solid rgba(255,255,255,.1); backdrop-filter: blur(16px); }
.help-brand { display: inline-flex; align-items: center; gap: 10px; min-width: 170px; }
.help-brand img { width: 42px; height: 42px; object-fit: contain; }
.help-brand strong, .help-brand small { display: block; line-height: 1.2; }
.help-brand strong { font-size: 20px; }
.help-brand small { margin-top: 3px; color: rgba(255,255,255,.66); font-size: 12px; }
.help-header nav { display: flex; gap: 28px; font-size: 14px; }
.help-header nav a { color: rgba(255,255,255,.76); }
.help-header nav a:hover, .help-header nav a:focus-visible { color: var(--lime); }
.header-action, .primary-action { display: inline-flex; align-items: center; justify-content: center; min-height: 44px; padding: 0 20px; color: #101820; background: var(--lime); border-radius: 8px; font-weight: 800; }

.guide-hero { color: var(--white); background: radial-gradient(circle at 80% 20%, rgba(18,100,255,.28), transparent 30%), linear-gradient(135deg, #061a1d 0%, #0c3328 55%, #071d2a 100%); }
.hero-inner { width: min(1180px, calc(100% - 80px)); margin: 0 auto; padding: 88px 0 82px; }
.kicker, .section-label { margin-bottom: 12px; color: var(--green); font-size: 13px; font-weight: 900; letter-spacing: .08em; text-transform: uppercase; }
.guide-hero .kicker { color: var(--lime); }
.guide-hero h1 { max-width: 840px; margin-bottom: 20px; font-size: clamp(42px, 6vw, 72px); line-height: 1.08; }
.hero-copy { max-width: 820px; margin-bottom: 28px; color: rgba(255,255,255,.78); font-size: 20px; }
.hero-meta { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 30px; }
.hero-meta span { padding: 7px 12px; color: rgba(255,255,255,.82); background: rgba(255,255,255,.08); border: 1px solid rgba(255,255,255,.14); border-radius: 999px; font-size: 13px; }

.guide-shell { width: min(1220px, calc(100% - 64px)); margin: 0 auto; display: grid; grid-template-columns: 220px minmax(0, 1fr); gap: 64px; align-items: start; }
.guide-toc { position: sticky; top: 102px; padding: 34px 0; }
.guide-toc p { margin-bottom: 14px; font-size: 13px; font-weight: 900; color: var(--muted); }
.guide-toc a { display: block; padding: 8px 12px; margin-left: -12px; color: var(--muted); border-left: 2px solid transparent; font-size: 14px; line-height: 1.35; }
.guide-toc a:hover, .guide-toc a:focus-visible { color: var(--green); background: #edf6f1; border-color: var(--green); }
.guide-article { min-width: 0; }
.guide-section { padding: 72px 0; border-bottom: 1px solid var(--line); }
.guide-section h2 { margin-bottom: 18px; font-size: clamp(30px, 4vw, 44px); line-height: 1.2; }
.guide-section h3 { margin: 42px 0 18px; font-size: 27px; line-height: 1.25; }
.guide-section > p { color: var(--muted); font-size: 17px; }
.intro-section { padding-top: 76px; }

.guide-figure { margin: 32px 0; overflow: hidden; background: #081925; border: 1px solid #d6e1e5; border-radius: 12px; box-shadow: var(--shadow); }
.guide-figure a { display: block; }
.guide-figure img { width: 100%; height: auto; }
.guide-figure figcaption { padding: 14px 18px; color: var(--muted); background: var(--white); font-size: 13px; }
.diagram-figure { background: #071825; }
.figure-grid { display: grid; gap: 22px; }
.figure-grid .guide-figure { margin-top: 22px; margin-bottom: 0; }
.two-up { grid-template-columns: repeat(2, minmax(0, 1fr)); }

.notice { margin: 28px 0; padding: 20px 22px; background: #eef6fb; border-left: 4px solid var(--blue); border-radius: 0 10px 10px 0; }
.notice strong { display: block; margin-bottom: 6px; }
.notice p, .notice ul { margin-bottom: 0; color: #445a69; }
.notice-important { background: #fff8e9; border-color: var(--orange); }
.notice-danger { background: #fff1f2; border-color: var(--danger); }
.notice-danger strong { color: #9e2732; }
.notice ul { padding-left: 20px; }

.step-list { padding: 0; margin: 30px 0; list-style: none; counter-reset: guide-step; }
.step-list li { counter-increment: guide-step; display: grid; grid-template-columns: 44px 180px minmax(0, 1fr); gap: 16px; align-items: start; padding: 20px 0; border-bottom: 1px solid var(--line); }
.step-list li::before { content: counter(guide-step); display: inline-grid; place-items: center; width: 34px; height: 34px; color: var(--white); background: var(--green); border-radius: 50%; font-size: 14px; font-weight: 900; }
.step-list strong { padding-top: 2px; }
.step-list span { color: var(--muted); }
.compact-steps li { grid-template-columns: 44px 190px minmax(0, 1fr); }

.definition-grid, .check-grid, .method-grid { display: grid; gap: 16px; margin: 28px 0; }
.definition-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.definition-grid > div, .check-grid > div, .method-grid article { padding: 22px; background: var(--soft); border: 1px solid var(--line); border-radius: 10px; }
.definition-grid strong, .check-grid strong { font-size: 18px; }
.definition-grid p, .check-grid p, .method-grid p { margin: 6px 0 0; color: var(--muted); }
.two-cards { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.check-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.method-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.method-grid article span { display: inline-grid; place-items: center; width: 34px; height: 34px; margin-bottom: 18px; color: var(--white); background: var(--green); border-radius: 50%; font-weight: 900; }
.method-grid h4 { margin-bottom: 8px; font-size: 18px; }

.phase-track { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin: 30px 0; padding: 24px; background: var(--green-dark); border-radius: 12px; }
.phase-track span { flex: 1; padding: 10px 8px; color: var(--white); text-align: center; background: rgba(255,255,255,.08); border: 1px solid rgba(255,255,255,.14); border-radius: 8px; font-weight: 800; }
.phase-track i { color: var(--lime); font-style: normal; font-weight: 900; }

.faq-list { border-top: 1px solid var(--line); }
.faq-list details { border-bottom: 1px solid var(--line); }
.faq-list summary { position: relative; padding: 22px 50px 22px 0; cursor: pointer; font-weight: 800; list-style: none; }
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary::after { content: "+"; position: absolute; right: 8px; top: 18px; color: var(--green); font-size: 28px; font-weight: 400; }
.faq-list details[open] summary::after { content: "−"; }
.faq-list details p { max-width: 760px; padding: 0 50px 20px 0; margin: 0; color: var(--muted); }

.guide-contact { display: flex; align-items: center; justify-content: space-between; gap: 40px; margin: 72px 0; padding: 34px; color: var(--white); background: var(--green-dark); border-radius: 14px; }
.guide-contact .section-label { color: var(--lime); }
.guide-contact h2 { margin-bottom: 8px; font-size: 28px; }
.guide-contact p { margin-bottom: 0; color: rgba(255,255,255,.72); }
.guide-contact .primary-action { flex: 0 0 auto; }

.site-footer { display: flex; justify-content: space-between; gap: 32px; padding: 36px max(32px, calc((100vw - 1180px) / 2)); color: var(--white); background: #06171b; }
.site-footer strong { font-size: 20px; }
.site-footer p { margin: 4px 0 0; color: rgba(255,255,255,.62); font-size: 13px; }
.site-footer > div:last-child { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 16px 24px; color: rgba(255,255,255,.7); font-size: 13px; }

@media (max-width: 980px) {
  .help-header nav { display: none; }
  .guide-shell { grid-template-columns: 1fr; }
  .guide-toc { display: none; }
  .method-grid { grid-template-columns: 1fr; }
  .intro-section { padding-top: 56px; }
}

@media (max-width: 720px) {
  html { scroll-padding-top: 74px; }
  .help-header { height: 64px; padding: 0 18px; }
  .help-brand { min-width: 0; }
  .help-brand img { width: 36px; height: 36px; }
  .help-brand small { display: none; }
  .header-action { min-height: 38px; padding: 0 14px; font-size: 13px; }
  .hero-inner { width: min(100% - 36px, 1180px); padding: 58px 0 56px; }
  .guide-hero h1 { font-size: 42px; }
  .hero-copy { font-size: 17px; }
  .guide-shell { width: min(100% - 36px, 1220px); }
  .guide-section { padding: 52px 0; }
  .guide-section h2 { font-size: 30px; }
  .guide-section h3 { font-size: 23px; }
  .two-up, .definition-grid, .two-cards, .check-grid { grid-template-columns: 1fr; }
  .step-list li, .compact-steps li { grid-template-columns: 38px minmax(0, 1fr); gap: 12px; }
  .step-list strong { grid-column: 2; }
  .step-list span { grid-column: 2; }
  .phase-track { flex-wrap: wrap; justify-content: center; padding: 18px; }
  .phase-track span { flex: 0 1 calc(50% - 24px); }
  .phase-track i { flex: 0 0 12px; }
  .guide-contact { align-items: flex-start; flex-direction: column; margin: 52px 0; padding: 26px 22px; }
  .guide-contact .primary-action { width: 100%; }
  .site-footer { display: grid; padding: 30px 20px; }
  .site-footer > div:last-child { justify-content: flex-start; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}