:root {
  --primary: #16a394;
  --primary-dark: #0c766c;
  --accent: #35c7b5;
  --ink: #17201d;
  --muted: #60706a;
  --line: #dfe6e3;
  --surface: #f3f6f4;
  --dark: #111715;
  --white: #fff;
  --font: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--surface);
  color: var(--ink);
  font-family: var(--font);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}
img { display: block; max-width: 100%; }
a { color: var(--primary-dark); text-decoration: none; }
a:hover { color: var(--primary); }
button { font: inherit; }
.container { width: min(1180px, calc(100% - 64px)); margin: 0 auto; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(17, 23, 21, .96);
  border-bottom: 1px solid rgba(255, 255, 255, .1);
  backdrop-filter: blur(16px);
}
.header-inner { display: flex; height: 76px; align-items: center; gap: 28px; }
.brand { display: inline-flex; align-items: center; flex: 0 0 auto; color: #fff; line-height: 1.1; }
.brand:hover { color: #fff; }
.brand img { width: 38px; height: 38px; object-fit: cover; }
.brand-copy { display: flex; flex-direction: column; margin-left: 10px; }
.brand-copy strong { font-size: .96rem; font-weight: 650; }
.brand-copy small { margin-top: 4px; color: #82918c; font-size: .54rem; letter-spacing: 1.2px; }
.nav { margin-left: auto; }
.nav-list { display: flex; align-items: center; gap: 28px; margin: 0; padding: 0; list-style: none; }
.nav-list a { color: #c9d2cf; font-size: .9rem; }
.nav-list a:hover, .nav-list a[aria-current="page"] { color: #fff; }
.nav-toggle {
  display: none;
  width: 42px;
  height: 42px;
  padding: 0;
  color: #fff;
  background: transparent;
  border: 0;
  cursor: pointer;
}
.nav-toggle span, .nav-toggle::before, .nav-toggle::after {
  display: block;
  width: 22px;
  height: 1px;
  margin: 6px auto;
  background: currentColor;
  content: "";
  transition: transform .2s, opacity .2s;
}
.nav-toggle[aria-expanded="true"] span { opacity: 0; }
.nav-toggle[aria-expanded="true"]::before { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"]::after { transform: translateY(-7px) rotate(-45deg); }
.btn {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  padding: 10px 20px;
  color: #0b1714;
  font-weight: 650;
  background: var(--accent);
  border: 1px solid var(--accent);
  border-radius: 6px;
}
.btn:hover { color: #0b1714; background: #58d5c5; border-color: #58d5c5; }
.btn-secondary { color: var(--ink); background: #fff; border-color: var(--line); }
.btn-secondary:hover { color: var(--primary-dark); background: #fff; border-color: #b7c8c2; }

.article-hero { padding: 66px 0 62px; color: #fff; background: var(--dark); }
.breadcrumbs { display: flex; flex-wrap: wrap; gap: 8px; margin: 0 0 30px; color: #8fa09a; font-size: .84rem; }
.breadcrumbs a { color: #b9c7c2; }
.breadcrumbs span::before { margin-right: 8px; color: #596762; content: "/"; }
.article-hero h1 {
  max-width: 880px;
  margin: 0;
  font-size: clamp(2.2rem, 5vw, 4rem);
  font-weight: 700;
  letter-spacing: -.025em;
  line-height: 1.18;
}
.lead { max-width: 760px; margin: 24px 0 0; color: #becbc7; font-size: 1.08rem; line-height: 1.85; }
.article-meta { display: flex; flex-wrap: wrap; gap: 10px 22px; margin-top: 30px; color: #879690; font-size: .84rem; }
.article-meta span + span { position: relative; }
.article-meta span + span::before { position: absolute; left: -12px; color: #4f5d58; content: "·"; }

.article-shell {
  display: grid;
  grid-template-columns: minmax(0, 790px) 270px;
  gap: 72px;
  align-items: start;
  padding-top: 64px;
  padding-bottom: 92px;
}
.article { min-width: 0; }
.article > :first-child { margin-top: 0; }
.article h2, .article h3 { scroll-margin-top: 105px; line-height: 1.35; }
.article h2 { margin: 56px 0 20px; font-size: 1.8rem; }
.article h3 { margin: 34px 0 12px; font-size: 1.2rem; }
.article p { margin: 0 0 20px; color: #33413c; }
.article strong { color: var(--ink); }
.article ul, .article ol { margin: 0 0 24px; padding-left: 1.35rem; color: #33413c; }
.article li { margin: 8px 0; padding-left: 4px; }
.article figure { margin: 34px 0; }
.article figure img { width: 100%; aspect-ratio: 16 / 8.6; object-fit: cover; border: 1px solid var(--line); border-radius: 6px; }
.article figcaption { margin-top: 10px; color: var(--muted); font-size: .82rem; text-align: center; }
.summary {
  margin-bottom: 38px;
  padding: 22px 24px;
  background: #dff1ed;
  border-left: 3px solid var(--primary);
}
.summary p { margin: 0; color: #2d4740; }
.note {
  margin: 28px 0;
  padding: 20px 22px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 6px;
}
.note strong { display: block; margin-bottom: 5px; }
.note p { margin: 0; color: var(--muted); font-size: .94rem; }
.steps {
  margin: 28px 0;
  padding: 0;
  list-style: none;
  counter-reset: steps;
}
.steps li {
  position: relative;
  min-height: 56px;
  margin: 0;
  padding: 0 0 24px 52px;
  counter-increment: steps;
}
.steps li::before {
  position: absolute;
  top: 0;
  left: 0;
  display: grid;
  width: 34px;
  height: 34px;
  place-items: center;
  color: #0b4f48;
  font-weight: 700;
  background: #c9ebe5;
  border-radius: 4px;
  content: counter(steps);
}
.steps li:not(:last-child)::after {
  position: absolute;
  top: 40px;
  bottom: 6px;
  left: 16px;
  width: 1px;
  background: #cbd8d3;
  content: "";
}
.compare { width: 100%; margin: 28px 0; border-collapse: collapse; background: #fff; font-size: .92rem; }
.compare th, .compare td { padding: 14px 16px; text-align: left; border: 1px solid var(--line); vertical-align: top; }
.compare th { color: #28413a; background: #e8f1ee; }
.article-end { margin-top: 58px; padding-top: 26px; border-top: 1px solid var(--line); }
.article-end p { color: var(--muted); font-size: .9rem; }

.toc { position: sticky; top: 110px; padding-left: 22px; border-left: 1px solid #cbd6d2; }
.toc h2 { margin: 0 0 16px; font-size: .84rem; }
.toc ol { margin: 0; padding: 0; list-style: none; }
.toc li { margin: 0 0 10px; }
.toc a { color: var(--muted); font-size: .88rem; line-height: 1.45; }
.toc a:hover { color: var(--primary-dark); }
.toc-cta { margin-top: 28px; padding-top: 24px; border-top: 1px solid var(--line); }
.toc-cta p { margin: 0 0 14px; color: var(--muted); font-size: .86rem; }

.related { padding: 76px 0; background: #fff; border-top: 1px solid var(--line); }
.section-title { display: flex; align-items: end; justify-content: space-between; gap: 20px; margin-bottom: 30px; }
.section-title h2 { margin: 0; font-size: 1.75rem; }
.section-title a { font-size: .9rem; }
.related-grid { display: grid; grid-template-columns: repeat(3, 1fr); border-top: 1px solid #ccd6d2; }
.related-card { min-height: 190px; padding: 26px 26px 20px; border-right: 1px solid #ccd6d2; }
.related-card:last-child { border-right: 0; }
.related-card small { color: var(--primary-dark); font-weight: 700; }
.related-card h3 { margin: 22px 0 10px; font-size: 1.08rem; line-height: 1.5; }
.related-card h3 a { color: var(--ink); }
.related-card h3 a:hover { color: var(--primary-dark); }
.related-card p { margin: 0; color: var(--muted); font-size: .86rem; }

.site-footer { padding: 62px 0 26px; color: #fff; background: #0b0f0e; }
.footer-grid { display: grid; grid-template-columns: 1.5fr 1fr 1fr; gap: 64px; }
.footer-intro { max-width: 480px; margin: 20px 0 0; color: #8f9d98; font-size: .88rem; }
.footer-col h2 { margin: 0 0 16px; font-size: .9rem; }
.footer-col ul { margin: 0; padding: 0; list-style: none; }
.footer-col li { margin: 9px 0; }
.footer-col a { color: #8f9d98; font-size: .88rem; }
.footer-col a:hover { color: #fff; }
.footer-bottom { margin-top: 48px; padding-top: 22px; color: #74817d; border-top: 1px solid rgba(255,255,255,.1); font-size: .8rem; }
.footer-bottom p { margin: 5px 0; }

:focus-visible { outline: 3px solid rgba(53, 199, 181, .55); outline-offset: 3px; }

@media (max-width: 960px) {
  .header-cta { display: none; }
  .article-shell { grid-template-columns: minmax(0, 1fr) 220px; gap: 42px; }
}

@media (max-width: 760px) {
  .container { width: min(100% - 40px, 1180px); }
  .header-inner { height: 68px; }
  .brand img { width: 34px; height: 34px; }
  .nav-toggle { display: block; margin-left: auto; }
  .nav {
    position: absolute;
    top: 68px;
    right: 0;
    left: 0;
    display: none;
    padding: 10px 20px 24px;
    background: var(--dark);
    border-bottom: 1px solid rgba(255,255,255,.1);
  }
  .nav.open { display: block; }
  .nav-list { align-items: stretch; flex-direction: column; gap: 0; }
  .nav-list a { display: block; padding: 12px 0; }
  .article-hero { padding: 46px 0 48px; }
  .article-hero h1 { font-size: clamp(2rem, 10vw, 2.8rem); }
  .lead { font-size: 1rem; }
  .article-meta { display: grid; grid-template-columns: 1fr 1fr; gap: 8px 16px; }
  .article-meta span + span::before { display: none; }
  .article-shell { display: block; padding-top: 44px; padding-bottom: 64px; }
  .article h2 { margin-top: 46px; font-size: 1.55rem; }
  .toc { display: none; }
  .compare-wrap { overflow-x: auto; }
  .compare { min-width: 620px; }
  .related { padding: 58px 0; }
  .related-grid { grid-template-columns: 1fr; }
  .related-card { min-height: 0; padding-inline: 4px; border-right: 0; border-bottom: 1px solid #ccd6d2; }
  .related-card:last-child { border-bottom: 0; }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 36px 24px; }
  .footer-brand { grid-column: 1 / -1; }
}

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