:root {
  --page-bg: #f4f8ff;
  --panel: #ffffff;
  --text: #061737;
  --muted: #65738a;
  --line: #dfe8f8;
  --blue: #1559ee;
  --blue-soft: #e9f2ff;
  --gold: #b9771e;
  --gold-soft: #fff3dd;
  --shadow: 0 18px 54px rgba(35, 73, 130, 0.13);
}

* {
  box-sizing: border-box;
}

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

body {
  min-width: 320px;
  min-height: 100vh;
  margin: 0;
  color: var(--text);
  font-family: Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
}

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

.site-header {
  display: flex;
  width: min(100% - 32px, 1080px);
  min-height: 72px;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  margin: 18px auto 0;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.92);
  padding: 0 22px;
  box-shadow: 0 10px 28px rgba(35, 73, 130, 0.08);
}

.brand {
  display: grid;
  gap: 3px;
  color: #111827;
  font-size: 22px;
  font-weight: 900;
  line-height: 1.1;
}

.brand span {
  color: var(--muted);
  font-size: 13px;
  font-weight: 700;
}

.top-nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 10px;
}

.top-nav a,
.article-nav a {
  display: inline-flex;
  min-height: 38px;
  align-items: center;
  border: 1px solid #d7e2f4;
  border-radius: 8px;
  background: #ffffff;
  color: #1e2b46;
  padding: 0 13px;
  font-size: 14px;
  font-weight: 800;
}

.top-nav a:first-child {
  background: var(--blue);
  color: #ffffff;
  border-color: var(--blue);
}

.article-shell {
  width: min(100% - 32px, 1080px);
  margin: 22px auto 56px;
}

.article-card {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--panel);
  box-shadow: var(--shadow);
}

.article-hero {
  border-bottom: 1px solid var(--line);
  background: linear-gradient(135deg, #ffffff 0%, #edf5ff 100%);
  padding: clamp(30px, 5vw, 58px);
}

.eyebrow {
  margin: 0;
  color: var(--blue);
  font-size: 14px;
  font-weight: 900;
}

h1 {
  max-width: 820px;
  margin: 12px 0 0;
  color: #111827;
  font-size: clamp(32px, 5vw, 52px);
  font-weight: 900;
  letter-spacing: 0;
  line-height: 1.16;
}

.lead {
  max-width: 780px;
  margin: 18px 0 0;
  color: #4f5f76;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.85;
}

.article-body {
  display: grid;
  gap: 26px;
  padding: clamp(24px, 4vw, 42px);
}

.article-body section {
  display: grid;
  gap: 12px;
}

h2 {
  margin: 0;
  color: #111827;
  font-size: 24px;
  font-weight: 900;
  line-height: 1.3;
}

p {
  margin: 0;
  color: #334155;
  font-size: 16px;
  font-weight: 500;
  line-height: 1.9;
  overflow-wrap: anywhere;
}

.note {
  border-left: 4px solid var(--gold);
  background: var(--gold-soft);
  padding: 14px 16px;
  color: #6b4b12;
  font-weight: 700;
}

.topic-links {
  border-top: 1px solid var(--line);
  padding-top: 24px;
}

.article-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.article-nav a[aria-current="page"] {
  background: var(--blue-soft);
  color: var(--blue);
  border-color: #bdd4ff;
}

@media (max-width: 640px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
    padding: 16px;
  }

  .top-nav {
    justify-content: flex-start;
  }

  .article-shell {
    width: min(100% - 20px, 1080px);
    margin-top: 12px;
  }

  .article-card {
    border-radius: 12px;
  }

  .article-hero {
    padding: 26px 20px;
  }

  h1 {
    font-size: 30px;
  }

  .article-body {
    padding: 22px 18px;
  }
}