/* ============ 全局样式 ============ */
:root {
  --bg: #f7f8fc;
  --card: #ffffff;
  --text: #1a1d29;
  --text-secondary: #5b6172;
  --primary: #4f6df5;
  --primary-dark: #3a56d4;
  --border: #e6e8f0;
  --shadow: 0 2px 12px rgba(30, 40, 90, 0.08);
  --radius: 12px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC",
               "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.8;
}

a { color: var(--primary); text-decoration: none; }
a:hover { color: var(--primary-dark); }

.container { max-width: 900px; margin: 0 auto; padding: 0 20px; }

/* ============ 顶部导航 ============ */
.navbar {
  background: var(--card);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}
.navbar-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.navbar-brand {
  font-weight: 700;
  font-size: 17px;
  color: var(--text);
}
.navbar-brand span { color: var(--primary); }
.navbar a.back-link {
  font-size: 14px;
  color: var(--text-secondary);
}

/* ============ 首页 ============ */
.hero { text-align: center; padding: 48px 20px 12px; }
.hero h1 { font-size: 30px; margin-bottom: 10px; }
.hero p { color: var(--text-secondary); max-width: 620px; margin: 0 auto; }

#graph {
  width: 100%;
  max-width: 1100px;
  height: 620px;
  margin: 0 auto;
}

.tip-bar {
  text-align: center;
  color: var(--text-secondary);
  font-size: 13px;
  padding-bottom: 30px;
}

.category-legend {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px 18px;
  padding: 8px 20px 20px;
  font-size: 13px;
  color: var(--text-secondary);
}
.category-legend .dot {
  display: inline-block;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  margin-right: 5px;
  vertical-align: middle;
}

/* ============ 详情页 ============ */
.node-header {
  background: var(--card);
  border-bottom: 1px solid var(--border);
  padding: 36px 0 28px;
}
.node-breadcrumb {
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 10px;
}
.node-title { font-size: 30px; margin-bottom: 6px; }
.node-tagline { color: var(--text-secondary); font-size: 16px; }

.node-body { padding: 32px 0 60px; }
.node-body .card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 32px 36px;
}
.node-body h2 {
  font-size: 21px;
  margin: 30px 0 12px;
  padding-left: 12px;
  border-left: 4px solid var(--primary);
}
.node-body h2:first-child { margin-top: 0; }
.node-body h3 { font-size: 17px; margin: 22px 0 8px; }
.node-body p { margin: 10px 0; color: #2a2e3d; }
.node-body ul, .node-body ol { margin: 10px 0 10px 24px; }
.node-body li { margin: 5px 0; }
.node-body strong { color: var(--text); }
.node-body blockquote {
  margin: 14px 0;
  padding: 12px 18px;
  background: #f0f3ff;
  border-left: 4px solid var(--primary);
  border-radius: 0 8px 8px 0;
  color: #39406b;
}
.node-body code {
  background: #eef0f7;
  padding: 2px 7px;
  border-radius: 5px;
  font-size: 0.9em;
  font-family: "SF Mono", Menlo, Consolas, monospace;
}
.node-body pre {
  background: #1e2233;
  color: #e6e9f5;
  padding: 16px 20px;
  border-radius: 10px;
  overflow-x: auto;
  margin: 14px 0;
  font-size: 13px;
  line-height: 1.6;
}
.node-body pre code { background: none; padding: 0; color: inherit; }
.node-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 14px 0;
  font-size: 14px;
}
.node-body th, .node-body td {
  border: 1px solid var(--border);
  padding: 9px 13px;
  text-align: left;
}
.node-body th { background: #f0f2fa; }

/* 相关节点 */
.related { margin-top: 36px; }
.related h2 { font-size: 19px; margin-bottom: 14px; }
.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(190px, 1fr));
  gap: 12px;
}
.related-card {
  display: block;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 14px 16px;
  color: var(--text);
  transition: all 0.15s ease;
}
.related-card:hover {
  border-color: var(--primary);
  box-shadow: var(--shadow);
  transform: translateY(-2px);
  color: var(--text);
}
.related-card .cat {
  font-size: 12px;
  color: var(--text-secondary);
  margin-bottom: 3px;
}
.related-card .name { font-weight: 600; font-size: 15px; }

/* 404 */
.not-found { text-align: center; padding: 100px 20px; }
.not-found h1 { font-size: 60px; color: var(--primary); margin-bottom: 12px; }

.footer {
  text-align: center;
  color: var(--text-secondary);
  font-size: 13px;
  padding: 30px 20px;
  border-top: 1px solid var(--border);
}