:root {
  --ink: #10243b;
  --ink-soft: #3d5065;
  --muted: #627180;
  --blue: #1559d6;
  --blue-deep: #0b347f;
  --teal: #00a99a;
  --paper: #f5f7f4;
  --surface: #fff;
  --line: rgba(16, 36, 59, 0.12);
  --max: 980px;
  --nav-height: 70px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: #f8fafc;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a {
  color: var(--blue);
  text-decoration: none;
}

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

.container {
  width: min(calc(100% - 40px), var(--max));
  margin-inline: auto;
}

.site-header {
  border-bottom: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: saturate(170%) blur(18px);
}

.nav-shell {
  display: flex;
  min-height: var(--nav-height);
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-weight: 900;
  letter-spacing: -0.02em;
}

.brand img {
  width: 34px;
  height: 34px;
  border-radius: 10px;
}

.brand span {
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
}

.back-link {
  display: inline-flex;
  min-height: 40px;
  align-items: center;
  padding: 0 15px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--ink);
  background: rgba(255, 255, 255, 0.72);
  font-size: 12px;
  font-weight: 750;
}

main {
  padding: 52px 0 90px;
}

.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  margin-bottom: 28px;
  color: var(--muted);
  font-size: 11px;
}

.breadcrumbs a {
  color: var(--ink-soft);
}

.article-head {
  max-width: 860px;
  padding-bottom: 42px;
  border-bottom: 1px solid var(--line);
}

.eyebrow {
  display: inline-flex;
  min-height: 29px;
  align-items: center;
  padding: 0 12px;
  border: 1px solid rgba(21, 89, 214, 0.16);
  border-radius: 999px;
  color: var(--blue);
  background: rgba(255, 255, 255, 0.7);
  font-size: 10px;
  font-weight: 850;
  letter-spacing: 0.09em;
}

.article-head h1,
.hub-head h1 {
  margin: 20px 0 18px;
  font-size: clamp(36px, 6vw, 62px);
  line-height: 1.15;
  letter-spacing: -0.05em;
  text-wrap: balance;
}

.lede {
  max-width: 780px;
  margin: 0;
  color: var(--ink-soft);
  font-size: 17px;
  line-height: 1.85;
}

.article-meta {
  margin: 22px 0 0;
  color: var(--muted);
  font-size: 11px;
}

.article-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 250px;
  gap: 54px;
  align-items: start;
  padding-top: 46px;
}

.article-body {
  min-width: 0;
}

.article-body h2 {
  margin: 42px 0 14px;
  font-size: 28px;
  line-height: 1.35;
  letter-spacing: -0.03em;
}

.article-body h3 {
  margin: 28px 0 10px;
  font-size: 20px;
  line-height: 1.4;
}

.article-body p,
.article-body li {
  color: var(--ink-soft);
  font-size: 15px;
  line-height: 1.9;
}

.article-body ul,
.article-body ol {
  padding-left: 1.3em;
}

.article-body strong {
  color: var(--ink);
}

.article-body a {
  text-decoration: underline;
  text-decoration-color: rgba(21, 89, 214, 0.3);
  text-underline-offset: 3px;
}

.callout {
  margin: 28px 0;
  padding: 22px 24px;
  border: 1px solid rgba(0, 169, 154, 0.18);
  border-radius: 20px;
  background: #ebf9f6;
}

.callout strong {
  display: block;
  margin-bottom: 5px;
  color: #086b62;
}

.callout p {
  margin: 0;
  font-size: 13.5px;
}

.comparison {
  width: 100%;
  margin: 22px 0 30px;
  border-collapse: collapse;
  font-size: 13px;
}

.comparison th,
.comparison td {
  padding: 13px 14px;
  border: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

.comparison th {
  color: #fff;
  background: var(--blue-deep);
}

.comparison th:first-child,
.comparison td:first-child {
  width: 26%;
  color: var(--ink);
  font-weight: 750;
}

.sidebar {
  position: sticky;
  top: 24px;
}

.sidebar-card {
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 24px;
  background: rgba(255, 255, 255, 0.82);
  box-shadow: 0 16px 40px rgba(20, 46, 75, 0.06);
}

.sidebar-card h2 {
  margin: 0 0 10px;
  font-size: 18px;
}

.sidebar-card p {
  margin: 0;
  color: var(--muted);
  font-size: 12px;
}

.sidebar-card .btn {
  margin-top: 18px;
}

.btn {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 0 20px;
  border: 1px solid transparent;
  border-radius: 999px;
  color: #fff;
  background: var(--blue);
  font-size: 13px;
  font-weight: 800;
  text-decoration: none;
}

.btn.secondary {
  color: var(--ink);
  background: #fff;
  border-color: var(--line);
}

.product-cta {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 22px;
  align-items: center;
  margin: 40px 0;
  padding: 28px;
  border-radius: 26px;
  color: #f7fbff;
  background:
    radial-gradient(circle at 92% 8%, rgba(113, 230, 216, 0.2), transparent 35%),
    #0b1728;
}

.product-cta h2 {
  margin: 0 0 7px;
  color: #fff;
  font-size: 23px;
}

.product-cta p {
  margin: 0;
  color: rgba(247, 251, 255, 0.62);
  font-size: 12px;
}

.product-cta .btn {
  color: var(--ink);
  background: #fff;
}

.article-faq details {
  border-top: 1px solid var(--line);
}

.article-faq details:last-child {
  border-bottom: 1px solid var(--line);
}

.article-faq summary {
  padding: 18px 0;
  font-size: 15px;
  font-weight: 750;
  cursor: pointer;
}

.article-faq p {
  margin: 0 0 18px;
  font-size: 13.5px;
}

.related {
  margin-top: 44px;
  padding-top: 28px;
  border-top: 1px solid var(--line);
}

.related h2 {
  margin-top: 0;
  font-size: 20px;
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.related a {
  padding: 17px 18px;
  border: 1px solid var(--line);
  border-radius: 16px;
  color: var(--ink);
  background: rgba(255, 255, 255, 0.74);
  font-size: 13px;
  font-weight: 720;
  text-decoration: none;
}

.hub-head {
  max-width: 880px;
  margin-bottom: 46px;
}

.guide-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.guide-card {
  display: flex;
  min-height: 250px;
  flex-direction: column;
  padding: 26px;
  border: 1px solid var(--line);
  border-radius: 25px;
  color: var(--ink);
  background: rgba(255, 255, 255, 0.82);
  box-shadow: 0 14px 38px rgba(20, 46, 75, 0.055);
  text-decoration: none;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.guide-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 22px 50px rgba(20, 46, 75, 0.1);
}

.guide-card small {
  color: var(--blue);
  font-size: 10px;
  font-weight: 850;
  letter-spacing: 0.08em;
}

.guide-card h2 {
  margin: 20px 0 9px;
  font-size: 23px;
  line-height: 1.35;
  letter-spacing: -0.025em;
}

.guide-card p {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
}

.guide-card span {
  margin-top: auto;
  padding-top: 22px;
  color: var(--blue);
  font-size: 12px;
  font-weight: 800;
}

.site-footer {
  padding: 34px 20px 42px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 11px;
  text-align: center;
}

.site-footer a {
  color: var(--ink-soft);
}

@media (max-width: 820px) {
  .article-layout {
    grid-template-columns: 1fr;
    gap: 34px;
  }

  .sidebar {
    position: static;
  }
}

@media (max-width: 600px) {
  .container {
    width: min(calc(100% - 28px), var(--max));
  }

  main {
    padding: 34px 0 68px;
  }

  .brand span {
    display: none;
  }

  .article-head h1,
  .hub-head h1 {
    font-size: clamp(33px, 10vw, 48px);
  }

  .article-layout {
    padding-top: 34px;
  }

  .guide-grid,
  .related-grid {
    grid-template-columns: 1fr;
  }

  .guide-card {
    min-height: 220px;
    padding: 22px;
  }

  .comparison {
    display: block;
    overflow-x: auto;
    white-space: nowrap;
  }

  .product-cta {
    grid-template-columns: 1fr;
  }

  .product-cta .btn {
    width: 100%;
  }
}