:root {
  color-scheme: light;
  --bg: #eef1f6;
  --card: #ffffff;
  --ink: #1f2d3d;
  --ink-soft: #64748b;
  --line: #eef0f4;
  --accent: #2563eb;
  --accent-soft: #f4f7fe;
  --radius: 22px;
  --shadow: 0 18px 50px rgba(30, 45, 80, 0.10);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC",
    "Microsoft YaHei", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: linear-gradient(180deg, #f7f9fc 0%, #eef1f6 100%);
  color: var(--ink);
  min-height: 100vh;
}

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

/* ---------------- Hero ---------------- */
.hero-wrap {
  max-width: 1180px;
  margin: 0 auto;
  padding: 40px 22px 80px;
}
.hero-card {
  background: var(--card);
  border-radius: 28px;
  box-shadow: var(--shadow);
  padding: 60px 50px 64px;
}
.hero-emoji { font-size: 40px; text-align: center; }
.hero-title {
  text-align: center;
  font-size: 56px;
  font-weight: 800;
  letter-spacing: 2px;
  margin: 14px 0 26px;
  color: #20334a;
}
.hero-slogan {
  text-align: center;
  background: #f3f5f9;
  color: #334155;
  font-size: 19px;
  font-weight: 600;
  padding: 16px;
  border-radius: 16px;
  max-width: 460px;
  margin: 0 auto;
}
.hero-subtitle {
  text-align: center;
  color: var(--ink-soft);
  font-size: 18px;
  margin: 26px 0 44px;
}

/* ---------------- Category grid ---------------- */
.cat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 26px;
}
.cat-card {
  background: #fff;
  border: 1px solid #f0f2f6;
  border-radius: var(--radius);
  box-shadow: 0 10px 30px rgba(30, 45, 80, 0.06);
  padding: 26px 24px 28px;
  transition: transform .18s ease, box-shadow .18s ease;
}
.cat-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 20px 44px rgba(30, 45, 80, 0.12);
}
.cat-head { display: flex; align-items: center; gap: 12px; }
.cat-icon { font-size: 30px; }
.cat-name { font-size: 26px; font-weight: 800; margin: 0; color: #20334a; }
.cat-desc { color: var(--ink-soft); margin: 12px 0 0; font-size: 15px; }
.cat-line { border: none; border-top: 1px solid var(--line); margin: 18px 0; }

.page-list { display: flex; flex-direction: column; gap: 12px; }
.page-item {
  display: flex;
  align-items: center;
  gap: 14px;
  background: var(--accent-soft);
  border: 1px solid #eaf0fd;
  border-radius: 16px;
  padding: 16px 18px;
  transition: background .15s ease, transform .15s ease;
}
.page-item:hover { background: #e9f0ff; transform: translateX(3px); }
.page-icon { font-size: 24px; }
.page-text { display: flex; flex-direction: column; flex: 1; min-width: 0; }
.page-title { font-weight: 700; font-size: 17px; color: #1e293b; }
.page-summary {
  color: var(--ink-soft);
  font-size: 13.5px;
  margin-top: 3px;
  line-height: 1.5;
}
.page-arrow { color: #94a3b8; font-size: 20px; font-weight: 700; }
.page-empty { color: #aab4c2; font-size: 14px; padding: 6px 2px; }

/* ---------------- Footer ---------------- */
.site-footer {
  text-align: center;
  padding: 26px;
  color: #9aa6b6;
  font-size: 13px;
  display: flex;
  gap: 18px;
  justify-content: center;
  align-items: center;
}
.site-footer a { color: #9aa6b6; }
.site-footer a:hover { color: var(--accent); }

/* ---------------- Article ---------------- */
.article-wrap { max-width: 860px; margin: 0 auto; padding: 36px 20px 70px; }
.article-card {
  background: #fff;
  border-radius: 24px;
  box-shadow: var(--shadow);
  padding: 40px 44px 50px;
}
.back-link {
  display: inline-block;
  color: var(--accent);
  font-size: 14px;
  margin-bottom: 18px;
}
.back-link:hover { text-decoration: underline; }
.article-meta {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
  color: var(--ink-soft);
  font-size: 13px;
  margin-bottom: 8px;
}
.article-icon { font-size: 28px; }
.article-cat {
  background: var(--accent-soft);
  color: var(--accent);
  padding: 4px 12px;
  border-radius: 999px;
  font-weight: 600;
}

/* ---------------- Markdown ---------------- */
.markdown-body { line-height: 1.85; font-size: 16.5px; color: #2b3a4d; }
.markdown-body h1 { font-size: 32px; margin: 18px 0 16px; color: #20334a; }
.markdown-body h2 { font-size: 25px; margin: 30px 0 14px; }
.markdown-body h3 { font-size: 20px; margin: 24px 0 12px; }
.markdown-body p { margin: 14px 0; }
.markdown-body img { max-width: 100%; border-radius: 12px; margin: 10px 0; }
.markdown-body pre {
  background: #0f172a; color: #e2e8f0; padding: 16px 18px;
  border-radius: 12px; overflow-x: auto; font-size: 14px;
}
.markdown-body code {
  background: #f1f5f9; padding: 2px 6px; border-radius: 6px;
  font-size: 14px; color: #be185d;
}
.markdown-body pre code { background: none; color: inherit; padding: 0; }
.markdown-body blockquote {
  border-left: 4px solid var(--accent);
  background: var(--accent-soft);
  margin: 16px 0; padding: 10px 18px; color: #475569; border-radius: 0 10px 10px 0;
}
.markdown-body table { border-collapse: collapse; width: 100%; margin: 16px 0; }
.markdown-body th, .markdown-body td { border: 1px solid #e2e8f0; padding: 8px 12px; }
.markdown-body th { background: #f8fafc; }
.markdown-body ul, .markdown-body ol { padding-left: 24px; }
.markdown-body a { color: var(--accent); text-decoration: underline; }

@media (max-width: 640px) {
  .hero-card { padding: 36px 22px 40px; }
  .hero-title { font-size: 38px; }
  .article-card { padding: 28px 22px 36px; }
}