:root{
  --bg:#f8fafc; --surface:#fff; --text:#0f172a; --text2:#475569;
  --accent:#2563eb; --accent-light:#eff6ff;
  --j-color:#2563eb; --s-color:#7c3aed;
  --green:#059669; --red:#dc2626; --orange:#d97706;
  --border:#e2e8f0; --radius:10px;
  --shadow:0 1px 3px rgba(0,0,0,0.06),0 1px 2px rgba(0,0,0,0.04);
}
*{margin:0;padding:0;box-sizing:border-box}
body{font-family:'PingFang SC','Microsoft YaHei',system-ui,sans-serif;background:var(--bg);color:var(--text);line-height:1.8;font-size:15px}
.topbar{background:#0f172a;color:#fff;padding:10px 24px;position:sticky;top:0;z-index:110;display:flex;align-items:center;gap:12px;flex-wrap:wrap;box-shadow:0 2px 8px rgba(0,0,0,0.15)}
.topbar h1{font-size:1.15rem;font-weight:700;white-space:nowrap}
.topbar .logo{height:22px;width:auto;object-fit:contain;margin-right:12px;vertical-align:middle;flex-shrink:0}
.group-toggle{display:flex;background:rgba(255,255,255,0.1);border-radius:24px;overflow:hidden;margin-left:32px}
.group-toggle button{padding:8px 22px;border:none;background:transparent;color:rgba(255,255,255,0.7);cursor:pointer;font-weight:700;font-size:0.9rem;transition:all .2s;white-space:nowrap}
.group-toggle button.active{background:#2563eb;color:#fff}
.group-toggle button.s-active{background:#7c3aed;color:#fff}
.group-toggle button:hover:not(.active):not(.s-active){background:rgba(255,255,255,0.12)}

.container{max-width:1150px;margin:0 auto;padding:24px 20px}
.tabs{display:flex;gap:8px;margin-bottom:24px;flex-wrap:wrap}
.tab{padding:10px 20px;border:1.5px solid var(--border);border-radius:var(--radius);background:var(--surface);cursor:pointer;font-size:0.9rem;font-weight:600;transition:all .15s}
.tab:hover{background:var(--accent-light);border-color:var(--accent)}
.tab.active{background:var(--accent);color:#fff;border-color:var(--accent)}
.section{display:none}
.section.active{display:block}

.j-show,.s-show{display:none}
body.j-mode .j-show{display:block}
body.j-mode .s-show{display:none}
body.s-mode .s-show{display:block}
body.s-mode .j-show{display:none}
body.j-mode span.j-show,body.j-mode strong.j-show,body.j-mode code.j-show{display:inline}
body.s-mode span.s-show,body.s-mode strong.s-show,body.s-mode code.s-show{display:inline}

.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:24px;margin-bottom:16px;box-shadow:var(--shadow)}
.card h2{font-size:1.1rem;margin-bottom:12px;display:flex;align-items:center;gap:8px}
.card h3{font-size:1rem;margin:16px 0 8px;color:var(--accent)}
.tag{display:inline-block;padding:2px 10px;border-radius:12px;font-size:0.7rem;font-weight:600;margin-left:8px}
.tag-green{background:#d1fae5;color:var(--green)}
.tag-red{background:#fee2e2;color:var(--red)}
.tag-orange{background:#fef3c7;color:var(--orange)}
.tag-purple{background:#ede9fe;color:var(--purple)}

table{width:100%;border-collapse:collapse;margin:12px 0;font-size:0.86rem}
th,td{border:1px solid var(--border);padding:9px 12px;text-align:left}
th{background:#f1f5f9;font-weight:700}
tr:hover{background:#fafbfc}
code{background:#f1f5f9;padding:2px 6px;border-radius:4px;font-family:'Consolas','Courier New',monospace;font-size:0.85em;color:#d946ef}
pre{background:#1e293b;color:#e2e8f0;padding:16px;border-radius:var(--radius);overflow-x:auto;font-size:0.8rem;line-height:1.6;margin:12px 0}
pre code{background:none;color:inherit;padding:0}
.checklist{list-style:none;padding:0}
.checklist li{padding:6px 0 6px 28px;position:relative}
.checklist li::before{content:'☐';position:absolute;left:0;color:var(--accent);font-size:1.1rem}
.timeline{position:relative;padding-left:24px;border-left:2px solid var(--accent);margin:16px 0}
.timeline-item{margin-bottom:20px;position:relative}
.timeline-item::before{content:'';position:absolute;left:-30px;top:6px;width:12px;height:12px;background:var(--accent);border-radius:50%;border:2px solid #fff;box-shadow:0 0 0 2px var(--accent)}
.timeline-item h4{font-size:0.95rem;margin-bottom:4px}
.timeline-item p{font-size:0.85rem;color:var(--text2)}

/* === Knowledge Tree === */
.knowledge-tree{display:flex;flex-direction:column;gap:12px}
.knowledge-category{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow)}
.knowledge-category .cat-header{padding:16px 20px;background:#f8fafc;cursor:pointer;display:flex;align-items:center;gap:10px;font-weight:700;font-size:1rem;border-bottom:1px solid transparent;transition:all .15s}
.knowledge-category .cat-header:hover{background:#eff6ff}
.knowledge-category .cat-header .arrow{transition:transform .2s;font-size:0.7rem}
.knowledge-category.open .cat-header{border-bottom-color:var(--border)}
.knowledge-category.open .cat-header .arrow{transform:rotate(90deg)}
.knowledge-category .cat-body{display:none;padding:0 20px 16px}
.knowledge-category.open .cat-body{display:block}
.knowledge-items{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:10px;margin-top:12px}
.knowledge-item{padding:12px 16px;border:1.5px solid var(--border);border-radius:8px;cursor:pointer;transition:all .15s;background:var(--surface);font-size:0.88rem;display:flex;align-items:center;gap:8px}
.knowledge-item:hover{border-color:var(--accent);background:var(--accent-light);transform:translateY(-1px);box-shadow:0 2px 6px rgba(37,99,235,0.1)}
.knowledge-item .ki-icon{font-size:1.2rem}
.knowledge-item .ki-badge{font-size:0.65rem;padding:1px 8px;border-radius:10px;margin-left:auto;white-space:nowrap}
.ki-badge-high{background:#fee2e2;color:var(--red)}
.ki-badge-mid{background:#fef3c7;color:var(--orange)}

/* === Modal === */
.modal-overlay{display:none;position:fixed;top:0;left:0;right:0;bottom:0;background:rgba(0,0,0,0.5);z-index:200;align-items:center;justify-content:center;padding:20px}
.modal-overlay.open{display:flex}
.modal{background:var(--surface);border-radius:16px;max-width:900px;width:100%;max-height:85vh;overflow-y:auto;box-shadow:0 20px 60px rgba(0,0,0,0.2);animation:modalIn .25s ease-out}
@keyframes modalIn{from{opacity:0;transform:scale(0.95) translateY(10px)}to{opacity:1;transform:scale(1) translateY(0)}}
.modal-header{position:sticky;top:0;background:var(--surface);padding:20px 24px 12px;border-bottom:1px solid var(--border);display:flex;align-items:center;justify-content:space-between;z-index:10}
.modal-header h2{font-size:1.15rem;margin:0}
.modal-close{width:32px;height:32px;border:none;background:#f1f5f9;border-radius:50%;cursor:pointer;font-size:1.1rem;display:flex;align-items:center;justify-content:center;transition:all .15s}
.modal-close:hover{background:#e2e8f0;color:var(--red)}
.modal-body{padding:20px 24px 24px}
.modal-body h3{color:var(--accent);margin:20px 0 10px;font-size:0.95rem}
.modal-body h3:first-child{margin-top:0}
.modal-body .explain-box{background:#f0f9ff;border-left:4px solid var(--accent);padding:14px 18px;border-radius:0 8px 8px 0;margin:12px 0;font-size:0.9rem}
.modal-body .qa-item{background:#fafafa;border:1px solid var(--border);border-radius:8px;padding:16px;margin:12px 0}
.modal-body .qa-item .qa-q{font-weight:700;margin-bottom:8px}
.modal-body .qa-item .qa-opts{margin:8px 0;font-size:0.88rem}
.modal-body .qa-item .qa-opts span{display:inline-block;margin-right:16px;padding:2px 8px;border-radius:4px}
.modal-body .qa-item .qa-ans{background:#d1fae5;padding:8px 12px;border-radius:6px;font-size:0.85rem;margin-top:8px}
.modal-body .qa-item .qa-ans strong{color:var(--green)}

.modal-body .warning-box{background:#fffbeb;border-left:4px solid var(--orange);padding:14px 18px;border-radius:0 8px 8px 0;margin:12px 0;font-size:0.88rem}
.modal-body .tip-box{background:#f0fdf4;border-left:4px solid var(--green);padding:14px 18px;border-radius:0 8px 8px 0;margin:12px 0;font-size:0.88rem}

.topic-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:14px}
.topic-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:18px;box-shadow:var(--shadow);transition:transform .15s;border-left:4px solid var(--accent)}
.topic-card:hover{transform:translateY(-2px)}
.topic-card h4{font-size:0.92rem;margin-bottom:8px}
.topic-card p{font-size:0.83rem;color:var(--text2);line-height:1.6}
.topic-card .priority{float:right;font-size:0.72rem;padding:2px 10px;border-radius:12px}
.p-high{background:#fee2e2;color:var(--red)}
.p-mid{background:#fef3c7;color:var(--orange)}
.p-low{background:#d1fae5;color:var(--green)}

/* ========== 响应式：平板 (≤768px) ========== */
@media(max-width:768px){
  body{font-size:14px}
  .container{padding:16px 12px}
  /* 顶栏 */
  .topbar{gap:8px;padding:8px 12px;flex-wrap:wrap}
  .topbar h1{font-size:0.95rem}
  .topbar .logo{height:18px;margin-right:6px}
  .group-toggle{margin-left:0;width:100%;justify-content:center}
  .group-toggle button{padding:8px 0;flex:1;text-align:center;font-size:0.85rem}
  /* 标签页 */
  .tabs{gap:4px}
  .tab{padding:8px 14px;font-size:0.8rem}
  /* 卡片 */
  .card{padding:16px;margin-bottom:12px}
  .card h2{font-size:1rem}
  .card h3{font-size:0.9rem}
  /* 知识树 */
  .knowledge-items{grid-template-columns:1fr}
  .knowledge-category .cat-header{padding:12px 14px;font-size:0.9rem}
  .knowledge-category .cat-body{padding:0 14px 12px}
  /* 表格 */
  table{font-size:0.78rem}
  th,td{padding:6px 8px}
  /* 弹窗 */
  .modal{max-height:92vh;border-radius:12px}
  .modal-header{padding:14px 16px 10px}
  .modal-body{padding:14px 16px}
  .modal-body .qa-item{padding:12px}
  /* 话题卡片 */
  .topic-grid{grid-template-columns:1fr;gap:10px}
  /* 代码块 */
  pre{padding:12px;font-size:0.75rem}
  /* 时间线 */
  .timeline{padding-left:18px}
  .timeline-item::before{left:-24px;width:10px;height:10px}
}

/* ========== 响应式：手机 (≤480px) ========== */
@media(max-width:480px){
  body{font-size:13.5px}
  .container{padding:10px 8px}
  /* 顶栏 */
  .topbar{padding:6px 8px}
  .topbar h1{font-size:0.85rem;white-space:normal;line-height:1.3}
  .topbar .logo{height:16px}
  .group-toggle button{padding:6px 0;font-size:0.78rem}
  /* 标签页 - 横向滚动 */
  .tabs{flex-wrap:nowrap;overflow-x:auto;gap:3px;padding-bottom:4px;-webkit-overflow-scrolling:touch;scrollbar-width:none}
  .tabs::-webkit-scrollbar{display:none}
  .tab{padding:7px 12px;font-size:0.75rem;flex-shrink:0;white-space:nowrap}
  /* 卡片 */
  .card{padding:12px;margin-bottom:10px;border-radius:8px}
  .card h2{font-size:0.92rem;gap:6px}
  .card h3{font-size:0.85rem}
  /* 知识树 */
  .knowledge-category .cat-header{padding:10px 12px;font-size:0.85rem;gap:6px}
  .knowledge-category .cat-body{padding:0 10px 10px}
  .knowledge-item{padding:10px 12px;font-size:0.8rem;gap:4px}
  .knowledge-item .ki-icon{font-size:1rem}
  /* 表格 - 横向滚动 */
  .card > table,.modal-body > table{display:block;overflow-x:auto;-webkit-overflow-scrolling:touch}
  table{font-size:0.72rem;min-width:400px}
  th,td{padding:5px 6px}
  /* 弹窗 - 全屏 */
  .modal-overlay{padding:0;align-items:flex-end}
  .modal-overlay.open{align-items:flex-end}
  .modal{max-width:100%;max-height:90vh;border-radius:16px 16px 0 0;width:100%}
  .modal-header{padding:12px 14px 8px}
  .modal-header h2{font-size:1rem}
  .modal-body{padding:12px 14px}
  .modal-body h3{font-size:0.85rem;margin:14px 0 8px}
  .modal-body .explain-box,.modal-body .warning-box,.modal-body .tip-box{padding:10px 14px;font-size:0.82rem}
  .modal-body .qa-item{padding:10px;border-radius:6px}
  .modal-body .qa-item .qa-ans{font-size:0.78rem}
  /* 话题卡片 */
  .topic-grid{gap:8px}
  .topic-card{padding:14px}
  .topic-card h4{font-size:0.85rem}
  .topic-card p{font-size:0.78rem}
  /* 代码块 */
  pre{padding:10px;font-size:0.7rem;border-radius:8px}
  code{font-size:0.8em;padding:1px 4px}
  /* 时间线 */
  .timeline{padding-left:16px}
  .timeline-item::before{left:-21px;width:8px;height:8px;top:4px}
  .timeline-item h4{font-size:0.85rem}
  /* 测验按钮 */
  .quiz-btn{padding:6px 10px;font-size:0.78rem;margin:2px 4px}
  /* 标签 */
  .tag{font-size:0.65rem;padding:1px 7px;margin-left:4px}
}

/* ========== 大屏优化 (>1200px) ========== */
@media(min-width:1200px){
  .container{max-width:1200px}
  .knowledge-items{grid-template-columns:repeat(auto-fill,minmax(260px,1fr))}
  .topic-grid{grid-template-columns:repeat(auto-fill,minmax(320px,1fr))}
}

/* === Interactive Quiz === */
.quiz-btn{padding:8px 14px;border:1.5px solid #d1d5db;border-radius:8px;background:#fff;cursor:pointer;font-size:0.85rem;margin:4px 6px;transition:all .15s;display:inline-block}
.quiz-btn:hover:not(:disabled){border-color:#3b82f6;background:#eff6ff}
.quiz-btn:disabled{cursor:default}
.quiz-btn.correct{background:#d1fae5!important;border-color:#059669!important;color:#065f46!important;font-weight:700!important}
.quiz-btn.wrong{background:#fee2e2!important;border-color:#dc2626!important;color:#991b1b!important}
.quiz-btn.dim{opacity:0.4}