/* ===== 学而思数学知识图谱 - 全局样式 ===== */
:root{
  --c-calc:#3b82f6; --c-num:#8b5cf6; --c-geo:#10b981; --c-trip:#f59e0b;
  --c-app:#ef4444; --c-count:#06b6d4; --c-logic:#64748b; --c-gen:#94a3b8;
  --bg:#f8fafc; --card:#fff; --border:#e2e8f0; --text:#1e293b; --muted:#64748b;
  --shadow:0 1px 3px rgba(0,0,0,.08),0 1px 2px rgba(0,0,0,.04);
}
*{box-sizing:border-box;margin:0;padding:0}
body{font-family:'Noto Sans CJK SC','Microsoft YaHei','PingFang SC',system-ui,sans-serif;background:var(--bg);color:var(--text);line-height:1.7;-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}
/* 导航 */
.nav{position:fixed;top:0;left:0;width:220px;height:100vh;background:#1e293b;color:#cbd5e1;padding:20px 0;overflow-y:auto;z-index:100;box-shadow:2px 0 8px rgba(0,0,0,.1)}
.nav .logo{padding:0 24px 20px;font-size:18px;font-weight:700;color:#fff;border-bottom:1px solid #334155;margin-bottom:12px}
.nav .logo small{display:block;font-size:11px;color:#64748b;font-weight:400;margin-top:4px}
.nav a{display:block;padding:10px 24px;color:#94a3b8;transition:.2s;font-size:14px;border-left:3px solid transparent}
.nav a:hover{background:#334155;color:#fff}
.nav a.active{background:#334155;color:#fff;border-left-color:var(--c-calc)}
.nav .section-title{padding:16px 24px 6px;font-size:11px;color:#475569;text-transform:uppercase;letter-spacing:1px}
/* 主内容 */
.main{margin-left:220px;padding:32px 40px;min-height:100vh}
.page-header{margin-bottom:28px}
.page-header h1{font-size:26px;font-weight:700;margin-bottom:6px}
.page-header .sub{color:var(--muted);font-size:14px}
/* 统计卡片 */
.stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:16px;margin-bottom:32px}
.stat{background:var(--card);border-radius:12px;padding:20px;box-shadow:var(--shadow);text-align:center}
.stat .num{font-size:32px;font-weight:700;line-height:1}
.stat .label{font-size:13px;color:var(--muted);margin-top:6px}
/* 卡片网格 */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:16px}
.card{background:var(--card);border-radius:10px;padding:18px;box-shadow:var(--shadow);border:1px solid var(--border);transition:.2s}
.card:hover{transform:translateY(-2px);box-shadow:0 4px 12px rgba(0,0,0,.1)}
.card h3{font-size:15px;margin-bottom:8px}
.card .meta{font-size:12px;color:var(--muted)}
/* 标签 */
.tag{display:inline-block;padding:2px 8px;border-radius:4px;font-size:11px;font-weight:600;margin:2px}
.tag-calc{background:#dbeafe;color:#1e40af}
.tag-num{background:#ede9fe;color:#5b21b6}
.tag-geo{background:#d1fae5;color:#065f46}
.tag-trip{background:#fef3c7;color:#92400e}
.tag-app{background:#fee2e2;color:#991b1b}
.tag-count{background:#cffafe;color:#155e75}
.tag-logic{background:#e2e8f0;color:#334155}
.tag-gen{background:#f1f5f9;color:#475569}
.tag-thread{background:#f1f5f9;color:#334155;border:1px solid #cbd5e1}
.tag-hub{background:#fef3c7;color:#92400e;border:1px solid #fbbf24}
/* 表格 */
.table-wrap{background:var(--card);border-radius:10px;box-shadow:var(--shadow);overflow:hidden;margin-top:16px}
table{width:100%;border-collapse:collapse;font-size:13px}
th{background:#f1f5f9;padding:10px 12px;text-align:left;font-weight:600;border-bottom:2px solid var(--border);position:sticky;top:0}
td{padding:8px 12px;border-bottom:1px solid var(--border)}
tr:hover{background:#f8fafc}
/* 筛选栏 */
.filters{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:20px;align-items:center}
.filters select,.filters input{padding:6px 10px;border:1px solid var(--border);border-radius:6px;font-size:13px;background:#fff}
.filters input{flex:1;min-width:200px}
.btn{padding:6px 14px;border:1px solid var(--border);border-radius:6px;background:#fff;cursor:pointer;font-size:13px;transition:.2s}
.btn:hover{background:#f1f5f9}
.btn.active{background:var(--c-calc);color:#fff;border-color:var(--c-calc)}
/* 暗线卡片 */
.thread-card{background:var(--card);border-radius:12px;padding:24px;box-shadow:var(--shadow);margin-bottom:16px;border-left:5px solid}
.thread-card h3{font-size:18px;margin-bottom:8px}
.thread-card .desc{color:var(--muted);margin-bottom:12px;font-size:14px}
/* 模型组 */
.model-card{background:var(--card);border-radius:12px;padding:20px;box-shadow:var(--shadow);margin-bottom:16px}
.model-card h3{color:var(--c-app);margin-bottom:6px}
.model-card .principle{color:var(--muted);font-size:14px;margin-bottom:12px;padding:10px;background:#f8fafc;border-radius:6px}
.model-card .topics{display:flex;flex-wrap:wrap;gap:4px}
/* 网络图 */
#graph-canvas{width:100%;height:70vh;background:#fff;border-radius:12px;box-shadow:var(--shadow);display:block;cursor:grab}
#graph-canvas:active{cursor:grabbing}
.graph-controls{display:flex;gap:8px;margin-bottom:12px;flex-wrap:wrap;align-items:center}
.legend{display:flex;flex-wrap:wrap;gap:10px;margin-top:12px;font-size:12px}
.legend-item{display:flex;align-items:center;gap:4px}
.legend-dot{width:12px;height:12px;border-radius:50%}
.node-detail{position:fixed;right:20px;top:80px;width:300px;max-height:70vh;overflow-y:auto;background:#fff;border-radius:10px;box-shadow:0 4px 20px rgba(0,0,0,.15);padding:16px;z-index:50;display:none}
.node-detail.show{display:block}
.node-detail h4{margin-bottom:8px}
.node-detail .methods{margin-top:10px}
.node-detail .method-item{font-size:12px;padding:3px 0;border-bottom:1px solid #f1f5f9}
/* 结论 */
.concl-section{margin-bottom:24px}
.concl-section h3{margin-bottom:10px;padding-bottom:6px;border-bottom:2px solid var(--border)}
.concl-item{background:var(--card);border-radius:8px;padding:12px 16px;margin-bottom:8px;box-shadow:var(--shadow);border-left:3px solid var(--c-calc)}
.concl-item .name{font-weight:600;font-size:14px}
.concl-item .formula{font-family:Consolas,monospace;font-size:13px;color:var(--c-num);margin:4px 0;background:#f8fafc;padding:4px 8px;border-radius:4px}
.concl-item .use{font-size:12px;color:var(--muted)}
/* 通用 */
.muted{color:var(--muted)}
.mt{margin-top:16px}
.mb{margin-bottom:16px}
.text-sm{font-size:13px}
.empty{padding:40px;text-align:center;color:var(--muted)}
/* 响应式 */
@media(max-width:768px){
  .nav{position:relative;width:100%;height:auto}
  .main{margin-left:0;padding:20px}
}