/* ===== 点点学习助手 - 共享样式 ===== */
*{margin:0;padding:0;box-sizing:border-box}
:root{
  --bg:#f5f3ff;
  --bg2:#ede9fe;
  --card:#fff;
  --card-hover:#faf9ff;
  --text:#1e1b4b;
  --sub:#7c7a9e;
  --sub-light:#a5a3c0;
  --border:#e8e4f0;
  --border-light:#f0edf7;
  --primary:#6366f1;
  --primary-light:#a5b4fc;
  --primary-bg:rgba(99,102,241,0.06);
  --primary-bg-hover:rgba(99,102,241,0.10);
  --accent:#f59e0b;
  --accent-light:#fcd34d;
  --accent-bg:rgba(245,158,11,0.08);
  --success:#10b981;
  --success-bg:rgba(16,185,129,0.08);
  --danger:#ef4444;
  --danger-bg:rgba(239,68,68,0.08);
  --shadow-sm:0 1px 3px rgba(99,102,241,0.04),0 1px 2px rgba(0,0,0,0.03);
  --shadow:0 4px 16px rgba(99,102,241,0.06),0 2px 8px rgba(0,0,0,0.04);
  --shadow-lg:0 8px 32px rgba(99,102,241,0.10),0 4px 16px rgba(0,0,0,0.06);
  --radius-sm:10px;
  --radius:14px;
  --radius-lg:20px;
}
[data-dark]{
  --bg:#0f0d1a;
  --bg2:#161228;
  --card:#1a1730;
  --card-hover:#1f1b38;
  --text:#e8e6f0;
  --sub:#9d9ab8;
  --sub-light:#6b6885;
  --border:#282545;
  --border-light:#201d3a;
  --primary:#818cf8;
  --primary-light:#6366f1;
  --primary-bg:rgba(129,140,248,0.08);
  --primary-bg-hover:rgba(129,140,248,0.14);
  --accent:#fbbf24;
  --accent-light:#f59e0b;
  --accent-bg:rgba(251,191,36,0.08);
  --shadow-sm:0 1px 3px rgba(0,0,0,0.15);
  --shadow:0 4px 16px rgba(0,0,0,0.2);
  --shadow-lg:0 8px 32px rgba(0,0,0,0.3);
}
body{font-family:"SF Pro Display","SF Pro Text","PingFang SC","Helvetica Neue",-apple-system,BlinkMacSystemFont,"Microsoft YaHei",sans-serif;background:var(--bg);color:var(--text);min-height:100vh;font-size:15px;line-height:1.65;transition:background .3s,color .3s;-webkit-overflow-scrolling:touch;overscroll-behavior-y:contain;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;font-weight:430}
html{touch-action:manipulation;-webkit-tap-highlight-color:transparent;scroll-behavior:smooth}

/* ===== 顶部导航 ===== */
.nav{
  display:flex;align-items:center;justify-content:space-between;
  padding:0 32px;height:60px;
  padding-left:max(32px, env(safe-area-inset-left));
  padding-right:max(32px, env(safe-area-inset-right));
  background:var(--card);border-bottom:1px solid var(--border);
  position:sticky;top:0;z-index:100;
  box-shadow:var(--shadow-sm);backdrop-filter:blur(12px);
  -webkit-backdrop-filter:blur(12px);
}
.nav-logo{font-size:20px;font-weight:700;letter-spacing:-.01em;background:linear-gradient(135deg,var(--primary),var(--accent));-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text;cursor:pointer;user-select:none;transition:opacity .2s}
.nav-logo:hover{opacity:.75}
.nav-right{display:flex;gap:8px;align-items:center}
.btn-icon{width:38px;height:38px;border:1px solid var(--border);border-radius:10px;background:var(--card);cursor:pointer;font-size:17px;display:flex;align-items:center;justify-content:center;color:var(--text);transition:all .2s}
.btn-icon:hover{background:var(--primary-bg);color:var(--primary);border-color:var(--primary-light)}
.btn-icon:active{transform:scale(.95)}

/* ===== 主体布局 ===== */
.layout{display:flex;min-height:calc(100vh - 60px)}

/* ===== 左侧工具条 + 抽屉 ===== */
.leftbar{
  display:flex;flex-shrink:0;
  position:sticky;top:60px;height:calc(100vh - 60px);
  border-right:1px solid var(--border);
  background:var(--card);
  transition:width .3s cubic-bezier(.16,1,.3,1);
  overflow:hidden;
  width:56px;
}
.leftbar.expand{width:320px}
.leftbar-rail{
  width:56px;flex-shrink:0;
  display:flex;flex-direction:column;
  align-items:center;padding:10px 0;gap:6px;
  border-right:1px solid var(--border);
}
.rail-btn{
  width:40px;height:40px;border-radius:10px;
  background:transparent;border:1px solid transparent;
  color:var(--sub);font-size:18px;cursor:pointer;
  display:flex;align-items:center;justify-content:center;
  transition:all .2s;
}
.rail-btn:hover{background:rgba(79,70,229,.08);color:var(--primary);border-color:var(--border)}
.rail-btn.on{background:var(--primary);color:#fff;border-color:var(--primary);box-shadow:0 4px 12px rgba(79,70,229,.35)}
.rail-spacer{flex:1}
.rail-btn:last-child{font-size:12px;color:var(--sub)}
.leftbar-drawer{
  flex:1;min-width:0;display:flex;flex-direction:column;
}
.sidebar-head{padding:14px 16px 10px;border-bottom:1px solid var(--border);display:flex;align-items:center;justify-content:space-between;flex-shrink:0}
.sidebar-head h4{font-size:12px;font-weight:600;color:var(--sub);text-transform:uppercase;letter-spacing:.08em}
.sidebar-body{flex:1;overflow-y:auto;padding:8px 0}
.toc-item{
  padding:8px 16px;cursor:pointer;font-size:13.5px;color:var(--sub);
  border-left:3px solid transparent;transition:all .15s;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;
}
.toc-item:hover{background:rgba(79,70,229,.06);color:var(--text);border-left-color:var(--primary-light)}
.toc-item.active{color:var(--primary);border-left-color:var(--primary);background:rgba(79,70,229,.08);font-weight:600}

/* ===== 侧栏知识树大纲 ===== */
.sidebar-chapter{margin-bottom:2px}
.sidebar-ch-head{
  display:flex;align-items:center;gap:6px;
  padding:8px 14px;cursor:pointer;user-select:none;
  transition:background .15s;
}
.sidebar-ch-head:hover{background:rgba(79,70,229,.06)}
.sidebar-ch-toggle{
  width:16px;height:16px;border-radius:4px;
  font-size:9px;display:flex;align-items:center;justify-content:center;
  flex-shrink:0;color:var(--sub);transition:transform .2s;
}
.sidebar-ch-toggle.open{transform:rotate(90deg);color:var(--primary)}
.sidebar-ch-title{
  font-size:13.5px;font-weight:600;color:var(--text);flex:1;
  white-space:nowrap;overflow:hidden;text-overflow:ellipsis;
}
.sidebar-ch-count{
  font-size:10.5px;color:var(--sub);background:rgba(79,70,229,.1);
  padding:1px 7px;border-radius:10px;flex-shrink:0;
}
.sidebar-ch-body{display:none}
.sidebar-ch-body.open{display:block}
.sidebar-kp{
  display:flex;align-items:center;gap:6px;
  padding:6px 14px 6px 26px;cursor:pointer;user-select:none;
  border-left:2px solid transparent;transition:all .15s;
}
.sidebar-kp:hover{background:rgba(79,70,229,.06);border-left-color:var(--primary-light)}
.sidebar-kp.active{background:rgba(79,70,229,.1);border-left-color:var(--primary);color:var(--primary)}
.sidebar-imp-dot{
  width:8px;height:8px;border-radius:50%;flex-shrink:0;
}
.sidebar-imp-dot.imp-必读{background:#ef4444}
.sidebar-imp-dot.imp-重要{background:#f59e0b}
.sidebar-imp-dot.imp-中等,.sidebar-imp-dot.imp-了解{background:var(--primary-light)}
.sidebar-kp-title{
  font-size:12px;color:var(--sub);flex:1;
  white-space:nowrap;overflow:hidden;text-overflow:ellipsis;
}
.sidebar-kp.active .sidebar-kp-title{color:var(--primary);font-weight:600}

/* ===== 主内容 ===== */
.main{flex:1;min-width:0;padding:32px}

/* ===== 上传相关 ===== */
.upload-wrap{max-width:1200px;margin:24px auto 0}
.upload-hero{text-align:center;margin-bottom:24px}
.upload-hero h2{font-size:32px;font-weight:700;letter-spacing:-.02em;background:linear-gradient(135deg,var(--primary),var(--accent));-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text;margin-bottom:8px}
.upload-hero p{font-size:14px;color:var(--sub)}
.btn-upload-main{
  display:inline-flex;align-items:center;gap:8px;
  padding:12px 28px;
  background:linear-gradient(135deg,var(--primary),#818cf8);
  color:#fff;border:none;border-radius:var(--radius-sm);font-size:15px;font-weight:600;
  cursor:pointer;transition:all .25s;
  box-shadow:0 4px 14px rgba(99,102,241,.35);
}
.btn-upload-main:hover{transform:translateY(-2px);box-shadow:0 8px 20px rgba(99,102,241,.45)}
.btn-upload-main:active{transform:translateY(0);box-shadow:0 2px 8px rgba(99,102,241,.25)}
.upload-bar{
  display:flex;align-items:center;justify-content:space-between;
  padding:14px 20px;background:var(--card);border-radius:var(--radius);
  box-shadow:var(--shadow);margin-bottom:20px;border:1px solid var(--border-light);
}
.upload-bar-info{font-size:13px;color:var(--sub)}
.upload-bar-info strong{color:var(--text);font-weight:700;margin-right:4px}
.upload-modal{width:92%;max-width:520px}
.upload-drop{
  border:2px dashed var(--border);border-radius:12px;
  padding:36px 24px;text-align:center;cursor:pointer;
  background:var(--bg);transition:all .25s;margin-bottom:14px;
}
.upload-drop:hover,.upload-drop.drag{border-color:var(--primary);background:var(--primary-bg);transform:scale(1.01)}
.upload-drop .upload-icon{font-size:42px;display:block;margin-bottom:10px}
.upload-drop h3{font-size:15px;margin-bottom:4px}
.upload-drop p{font-size:12px;color:var(--sub)}

/* ===== 加载进度 ===== */
.loading-wrap{max-width:480px;margin:80px auto;text-align:center}
.spinner{width:48px;height:48px;border:4px solid var(--border-light);border-top-color:var(--primary);border-radius:50%;animation:spin .8s linear infinite;margin:0 auto 20px}
@keyframes spin{to{transform:rotate(360deg)}}
.loading-title{font-size:18px;font-weight:600;margin-bottom:8px;color:var(--text)}
.loading-sub{font-size:13px;color:var(--sub)}
.progress-bar-wrap{margin:20px 0;background:var(--border-light);border-radius:99px;height:8px;overflow:hidden}
.progress-bar{height:100%;background:linear-gradient(90deg,var(--primary),var(--accent));border-radius:99px;transition:width .5s ease}
.steps{display:flex;justify-content:center;gap:32px;margin:24px 0}
.step{display:flex;align-items:center;gap:8px;opacity:.4;font-size:13px;font-weight:500;transition:opacity .3s}
.step.on{opacity:1;color:var(--primary)}
.step.done{opacity:.7}
.step-dot{width:28px;height:28px;border-radius:50%;background:var(--border);display:flex;align-items:center;justify-content:center;font-size:13px;font-weight:700;transition:all .3s;flex-shrink:0}
.step.on .step-dot{background:var(--primary);color:#fff;box-shadow:0 0 0 4px rgba(99,102,241,.2)}
.step.done .step-dot{background:var(--success);color:#fff}

/* ===== 书籍信息栏 ===== */
.book-bar{
  display:flex;align-items:center;gap:14px;flex-wrap:wrap;
  padding:18px 22px;background:var(--card);border-radius:var(--radius);
  box-shadow:var(--shadow);margin-bottom:24px;border:1px solid var(--border-light);
}
.book-icon{font-size:40px;flex-shrink:0}
.book-info{flex:1;min-width:120px}
.book-name{font-size:18px;font-weight:600;margin-bottom:3px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;color:var(--text)}
.book-meta{font-size:13px;color:var(--sub)}

/* 内联统计标签 */
.stat-inline{display:flex;gap:8px;flex-wrap:wrap;flex-shrink:0}
.stat-pill{
  font-size:13px;font-weight:600;color:var(--primary);
  padding:5px 12px;border-radius:20px;
  background:var(--primary-bg);
  border:1px solid rgba(99,102,241,0.12);
  white-space:nowrap;
}

/* ===== 书籍库（首页网格） ===== */
.library-wrap{margin-top:24px}
.library-head{
  display:flex;align-items:center;justify-content:space-between;
  margin-bottom:18px;
}
.library-head h3{font-size:18px;font-weight:600}
.library-grid{
  display:grid;
  grid-template-columns:repeat(6,1fr);
  gap:18px;
}
@media(max-width:1400px){.library-grid{grid-template-columns:repeat(5,1fr)}}
@media(max-width:1100px){.library-grid{grid-template-columns:repeat(4,1fr)}}
@media(max-width:820px){.library-grid{grid-template-columns:repeat(3,1fr)}}
@media(max-width:560px){.library-grid{grid-template-columns:repeat(2,1fr)}}
.book-card{
  background:var(--card);border-radius:var(--radius-lg);
  box-shadow:var(--shadow-sm);border:1px solid var(--border-light);overflow:hidden;
  cursor:pointer;transition:all .25s cubic-bezier(.16,1,.3,1);
  display:flex;flex-direction:column;
}
.book-card:hover{
  transform:translateY(-4px);
  box-shadow:var(--shadow-lg);border-color:var(--primary-light);
}
.book-card:active{transform:scale(.98)}
.book-cover{
  width:100%;aspect-ratio:200/283;
  background:linear-gradient(135deg,#ede9fe 0%,#fce7f3 50%,#e0f2fe 100%);
  position:relative;overflow:hidden;
  display:flex;align-items:center;justify-content:center;
}
[data-dark] .book-cover{
  background:linear-gradient(135deg,#312e81 0%,#831843 50%,#1e3a5f 100%);
}
.book-cover img{
  width:100%;height:100%;object-fit:cover;
  transition:transform .4s ease;
}
.book-card:hover .book-cover img{transform:scale(1.05)}
.book-cover-fallback{
  font-size:48px;font-weight:800;color:rgba(255,255,255,.7);
}
.book-badge{
  position:absolute;top:8px;right:8px;
  background:rgba(34,197,94,.92);color:#fff;
  font-size:11px;padding:3px 8px;border-radius:10px;
  font-weight:600;backdrop-filter:blur(8px);
  box-shadow:0 2px 6px rgba(0,0,0,.15);
}
.book-del{
  position:absolute;top:6px;left:6px;
  width:28px;height:28px;border-radius:50%;
  background:rgba(239,68,68,.92);color:#fff;
  display:flex;align-items:center;justify-content:center;
  font-size:14px;font-weight:600;
  opacity:0;transform:scale(.8);
  transition:all .2s;cursor:pointer;z-index:3;
  box-shadow:0 2px 8px rgba(239,68,68,.4);
  border:2px solid #fff;
}
.book-card:hover .book-del{opacity:1;transform:scale(1)}
.book-del:hover{background:#dc2626;transform:scale(1.1)}
.book-info{
  padding:12px 14px 14px;
}
.book-title{
  font-size:14px;font-weight:600;
  white-space:nowrap;overflow:hidden;text-overflow:ellipsis;
  margin-bottom:6px;
}
.book-meta{
  font-size:12.5px;color:var(--sub);
  display:flex;gap:4px;align-items:center;
}
.book-actions{
  display:flex;gap:6px;margin-top:8px;
}
.btn-book-action{
  flex:1;padding:6px 8px;border:1px solid var(--border);border-radius:8px;
  background:var(--card);cursor:pointer;font-size:12px;color:var(--text);
  transition:all .2s;text-align:center;font-weight:500;
}
.btn-book-action:hover{border-color:var(--primary);color:var(--primary);background:var(--primary-bg)}
.btn-book-action:active{transform:scale(.97)}
.btn-book-action.primary{
  background:linear-gradient(135deg,var(--primary),#818cf8);
  color:#fff;border-color:transparent;font-weight:600;
}
.btn-book-action.primary:hover{color:#fff;opacity:.92}
.btn-sm{
  padding:8px 18px;border:1.5px solid var(--border);border-radius:var(--radius-sm);
  background:var(--card);cursor:pointer;font-size:13px;color:var(--text);
  white-space:nowrap;transition:all .2s;font-weight:500;
}
.btn-sm:hover{border-color:var(--primary);color:var(--primary);background:var(--primary-bg)}
.btn-sm:active{transform:scale(.97)}

/* 表单输入（登录/管理页复用） */
.form-input {
  width:100%;padding:13px 16px;border:2px solid var(--border);
  border-radius:var(--radius-sm);font-size:15px;background:var(--bg);
  color:var(--text);outline:none;transition:all .25s;
}
.form-input:focus{border-color:var(--primary);box-shadow:0 0 0 4px var(--primary-bg);background:var(--card)}

/* ===== 本页知识点卡片布局 ===== */
.kp-page-wrap{background:transparent;border-radius:var(--radius-lg);overflow:hidden}
.kp-page-head{
  display:flex;align-items:center;justify-content:space-between;
  padding:20px 24px;background:var(--card);border-radius:var(--radius-lg) var(--radius-lg) 0 0;
  border:1px solid var(--border-light);border-bottom:none;
}
.kp-page-head h3{font-size:18px;font-weight:600}
.kp-chapter-section{
  padding:20px 24px;background:var(--card);border:1px solid var(--border-light);
  border-top:none;
}
.kp-chapter-section:last-child{border-radius:0 0 var(--radius-lg) var(--radius-lg)}
.kp-chapter-head{
  display:flex;align-items:center;gap:10px;margin-bottom:14px;
}
.kp-chapter-head h3{font-size:16px;font-weight:600;color:var(--primary);flex:1}
.kp-chapter-count{
  font-size:12.5px;color:var(--sub);background:var(--primary-bg);
  padding:3px 12px;border-radius:20px;font-weight:500;
}
.kp-cards{display:flex;flex-direction:column;gap:10px}
.kp-card{
  background:var(--bg);border:1px solid var(--border-light);border-radius:var(--radius-sm);
  padding:14px 16px;transition:all .2s;
}
.kp-card:hover{box-shadow:var(--shadow);border-color:var(--primary-light);transform:translateY(-1px)}
.kp-card-top{
  display:flex;align-items:center;gap:10px;margin-bottom:6px;
}
.kp-card-title{font-size:15px;font-weight:600;color:var(--text);flex:1}
.kp-card-summary{
  font-size:14px;line-height:1.75;color:var(--sub);
  margin-bottom:8px;padding-left:2px;
}
.kp-card-actions{display:flex;gap:8px}
.kp-card-subs{
  margin-top:10px;padding-top:10px;
  border-top:1px dashed var(--border);
  display:flex;flex-direction:column;gap:6px;
}
.kp-card-sub{
  display:flex;align-items:center;gap:8px;
  padding:8px 12px;border-radius:var(--radius-sm);
  background:var(--card);border:1px solid var(--border-light);
  transition:all .2s;cursor:pointer;
}
.kp-card-sub:hover{border-color:var(--primary-light);box-shadow:var(--shadow-sm);transform:translateX(2px)}
.kp-card-sub.loading{opacity:.6;pointer-events:none}
.kp-card-sub:active{transform:scale(.98)}

/* ===== 章节节点 ===== */
.chapter{
  border-bottom:1px solid var(--border);
}
.chapter-head{
  display:flex;align-items:center;gap:10px;
  padding:16px 24px;cursor:pointer;
  background:linear-gradient(135deg,rgba(79,70,229,.04),rgba(245,158,11,.02));
  transition:background .15s;user-select:none;
}
.chapter-head:hover{background:rgba(79,70,229,.08)}
.ch-toggle{
  width:24px;height:24px;border-radius:6px;
  background:var(--primary);color:#fff;
  display:flex;align-items:center;justify-content:center;
  font-size:12px;flex-shrink:0;transition:transform .2s;
}
.ch-toggle.open{transform:rotate(90deg)}
.ch-title{font-size:16px;font-weight:600;color:var(--primary);flex:1}
.ch-count{font-size:12.5px;color:var(--sub);background:rgba(79,70,229,.1);padding:2px 10px;border-radius:20px}

.chapter-body{padding:12px 16px 16px 44px;display:none}
.chapter-body.open{display:block}
.ch-summary{
  background:var(--primary-bg);
  border-left:3px solid var(--primary);
  border-radius:0 10px 10px 0;
  padding:12px 16px;
  margin:0 0 14px 0;
  position:relative;
}
.ch-summary-label{
  font-size:12px;font-weight:600;color:var(--primary);
  letter-spacing:.5px;margin-bottom:6px;text-transform:uppercase;opacity:.85;
}
.ch-summary-text{
  font-size:14px;line-height:1.8;color:var(--text);opacity:.9;word-break:break-word;
}

/* ===== 知识点节点 ===== */
.kp{
  border:1px solid var(--border);border-radius:var(--radius-sm);
  margin-bottom:10px;overflow:hidden;transition:all .2s;
  background:var(--bg);
}
.kp:hover{box-shadow:var(--shadow);border-color:var(--primary-light)}
.kp-head{
  display:flex;align-items:flex-start;gap:10px;
  padding:13px 14px;cursor:pointer;user-select:none;
}
.kp-toggle{
  width:22px;height:22px;border-radius:6px;border:1.5px solid var(--border);
  display:flex;align-items:center;justify-content:center;font-size:11px;
  flex-shrink:0;margin-top:1px;transition:all .2s;color:var(--sub);
}
.kp.has-sub .kp-toggle{border-color:var(--primary-light);color:var(--primary)}
.kp.open .kp-toggle{background:var(--primary);color:#fff;border-color:var(--primary);transform:rotate(90deg)}
.importance{
  font-size:11.5px;font-weight:600;padding:2px 8px;border-radius:20px;flex-shrink:0;margin-top:2px;
}
.imp-必读{background:linear-gradient(135deg,#ef4444,#dc2626);color:#fff}
.imp-重要{background:linear-gradient(135deg,#f59e0b,#d97706);color:#fff}
.imp-中等,.imp-了解{background:var(--primary-bg);color:var(--primary)}
.kp-title{font-size:14px;font-weight:600;flex:1;line-height:1.5}

/* ===== 知识点详情 ===== */
.kp-body{padding:0 14px 14px 14px;display:none}
.kp.open .kp-body{display:block}
.kp-summary{
  font-size:14px;line-height:1.75;color:var(--text);
  padding:10px 14px;background:var(--primary-bg);
  border-left:3px solid var(--primary);border-radius:0 8px 8px 0;
  margin-bottom:10px;
}
.kp-actions{display:flex;gap:8px;margin-top:4px}
.btn-action{
  padding:7px 16px;border-radius:8px;font-size:13px;font-weight:600;
  cursor:pointer;transition:all .2s;border:1.5px solid var(--border);
  background:var(--card);color:var(--text);
}
.btn-action:hover{border-color:var(--primary);color:var(--primary);background:var(--primary-bg)}
.btn-action:active{transform:scale(.97)}
.btn-action.primary{background:var(--primary);color:#fff;border-color:var(--primary)}
.btn-action.primary:hover{background:var(--primary-light);border-color:var(--primary-light)}

/* ===== 子知识点 ===== */
.sub-kps{
  margin-top:10px;padding-top:10px;
  border-top:1px dashed var(--border);
}
.sub-kp{
  padding:10px 12px;border-radius:8px;
  background:var(--card);border:1px solid var(--border);
  margin-bottom:8px;cursor:pointer;transition:all .2s;
}
.sub-kp:hover{border-color:var(--primary-light);box-shadow:0 2px 10px rgba(79,70,229,.1)}
.sub-kp-head{display:flex;align-items:center;gap:8px;margin-bottom:0}
.sub-kp.open .sub-kp-head{margin-bottom:8px}
.sub-toggle{
  width:18px;height:18px;border-radius:4px;border:1px solid var(--border);
  display:flex;align-items:center;justify-content:center;font-size:10px;
  flex-shrink:0;color:var(--sub);transition:transform .2s;
}
.sub-kp.open .sub-toggle{transform:rotate(90deg)}
.sub-title{font-size:13px;font-weight:600;flex:1}
.sub-detail{display:none;padding-top:8px}
.sub-kp.open .sub-detail{display:block}
.sub-summary{font-size:12.5px;color:var(--sub);line-height:1.65;margin-bottom:6px}
.sub-actions{display:flex;gap:6px}
.btn-sub{
  padding:4px 10px;border-radius:6px;font-size:11px;font-weight:500;
  cursor:pointer;border:1px solid var(--border);background:var(--card);color:var(--text);transition:all .2s;
}
.btn-sub:hover{border-color:var(--primary);color:var(--primary)}
.btn-sub.primary{background:var(--primary);color:#fff;border-color:var(--primary)}

/* ===== 弹窗 ===== */
.overlay{
  position:fixed;inset:0;background:rgba(0,0,0,.45);backdrop-filter:blur(8px);
  -webkit-backdrop-filter:blur(8px);
  z-index:500;display:flex;align-items:center;justify-content:center;
  animation:fadein .25s;
}
@keyframes fadein{from{opacity:0}to{opacity:1}}
.modal{
  background:var(--card);border-radius:var(--radius-lg);
  width:92%;max-width:760px;max-height:85vh;
  overflow:hidden;box-shadow:var(--shadow-lg);
  animation:slideup .3s cubic-bezier(0.16,1,0.3,1);
  display:flex;flex-direction:column;
}
@keyframes slideup{from{opacity:0;transform:translateY(32px)}to{opacity:1;transform:translateY(0)}}
.modal-head{
  display:flex;align-items:center;justify-content:space-between;
  padding:20px 24px;border-bottom:1px solid var(--border-light);flex-shrink:0;
}
.modal-tools{display:flex;align-items:center;gap:8px;flex-shrink:0;flex-wrap:nowrap}
.modal-tool-btn{width:32px;height:32px;border:1.5px solid var(--border);border-radius:8px;background:var(--card);cursor:pointer;font-size:14px;color:var(--text);display:flex;align-items:center;justify-content:center;transition:all .2s;flex-shrink:0;padding:0;line-height:1}
.modal-tool-btn:hover{background:var(--primary);color:#fff;border-color:var(--primary)}
.modal-tool-btn:active{transform:scale(.95)}
.font-size-label{font-size:13px;color:var(--text);font-weight:600;min-width:36px;text-align:center;flex-shrink:0}
.modal-close{width:36px;height:36px;border:1.5px solid var(--border);border-radius:var(--radius-sm);background:var(--card);cursor:pointer;font-size:18px;color:var(--text);display:flex;align-items:center;justify-content:center;transition:all .2s;flex-shrink:0}
.modal-close:hover{background:var(--danger);color:#fff;border-color:var(--danger)}
.modal-close:active{transform:scale(.95)}
.modal-body{padding:24px;overflow-y:auto;flex:1}

/* 深度讲解 —— 2 节卡片布局 */
.explain-md h2{font-size:1.05em;font-weight:700;margin:10px 0 2px;padding:10px 14px 10px 38px;border-radius:10px;position:relative;line-height:1.35;text-align:left;letter-spacing:.01em}
.explain-md h2::before{position:absolute;left:10px;top:50%;transform:translateY(-50%);width:22px;height:22px;border-radius:6px;display:flex;align-items:center;justify-content:center;font-size:13px;background:rgba(255,255,255,.9)}
.explain-md h2:first-child{margin-top:0}
.explain-md h2 + p{margin-top:4px;padding:10px 14px;border-radius:10px;line-height:1.55}
.explain-md h3{font-size:1em;font-weight:600;color:var(--text);margin:12px 0 6px}
.explain-md p{font-size:1em;line-height:1.55;margin-bottom:8px;color:var(--text)}
.explain-md strong{color:var(--primary);font-weight:700}
.explain-md blockquote{border-left:4px solid var(--accent);background:linear-gradient(135deg,rgba(245,158,11,.08),rgba(236,72,153,.06));padding:12px 16px;border-radius:0 8px 8px 0;margin:10px 0;color:var(--text);font-style:normal;font-size:1em;line-height:1.65;font-weight:500}
.explain-md ul,.explain-md ol{padding-left:22px;margin-bottom:10px}
.explain-md li{margin-bottom:6px;font-size:1em;line-height:1.65}
.explain-md li::marker{font-weight:700;color:var(--primary)}
.explain-md code{background:rgba(79,70,229,.1);padding:1px 5px;border-radius:4px;font-size:.85em;color:var(--primary)}
.explain-md pre{background:rgba(79,70,229,.06);padding:10px 14px;border-radius:8px;margin:10px 0;overflow:auto}
.explain-md pre code{background:none;padding:0;font-size:.85em;color:inherit}

/* 📖 解释 卡片 */
.explain-md h2.core-card{background:linear-gradient(135deg,#e0e7ff,#c7d2fe);color:#3730a3;border:1px solid #a5b4fc;box-shadow:0 2px 6px rgba(79,70,229,.12)}
.explain-md h2.core-card::before{content:'📖'}
.explain-md h2.core-card + p{background:linear-gradient(135deg,rgba(224,231,255,.25),rgba(199,210,254,.12));border:1px solid rgba(165,180,252,.2);color:#3730a3}
/* 🌰 举个例子 卡片 */
.explain-md h2.example-card{background:linear-gradient(135deg,#fed7aa,#fdba74);color:#9a3412;border:1px solid #fb923c;box-shadow:0 2px 6px rgba(249,115,22,.12)}
.explain-md h2.example-card::before{content:'🌰'}
.explain-md h2.example-card + p{background:linear-gradient(135deg,rgba(254,215,170,.25),rgba(253,186,116,.12));border:1px solid rgba(251,146,60,.2);color:#9a3412}


.toast{
  position:fixed;top:72px;right:20px;z-index:999;
  padding:14px 22px;border-radius:var(--radius-sm);font-size:14px;font-weight:500;
  background:var(--card);border:1px solid var(--border-light);
  box-shadow:var(--shadow-lg);
  animation:toast-in .3s cubic-bezier(.16,1,.3,1);max-width:380px;
  display:flex;align-items:center;gap:10px;
}
@keyframes toast-in{from{opacity:0;transform:translateY(-12px)}to{opacity:1;transform:translateY(0)}}
.toast.ok{border-left:4px solid var(--success)}
.toast.err{border-left:4px solid var(--danger)}
.toast.info{border-left:4px solid var(--primary)}

/* 空态 */
.empty{text-align:center;padding:60px 20px;color:var(--sub)}
.empty-icon{font-size:56px;margin-bottom:16px;opacity:.5}
.empty h3{font-size:18px;margin-bottom:8px;color:var(--text)}

/* ===== 设置面板 ===== */
.settings-section{
  margin-bottom:24px;
}
.settings-label{
  font-size:13px;font-weight:700;color:var(--sub);text-transform:uppercase;
  letter-spacing:.05em;margin-bottom:12px;display:block;
}
.settings-hint{
  font-size:12px;color:var(--sub);margin-top:6px;
}

.provider-btn{
  flex:1;padding:20px 16px;border:2px solid var(--border);border-radius:16px;
  background:var(--card);cursor:pointer;text-align:center;transition:all .25s;
  color:var(--text);position:relative;overflow:hidden;
}
.provider-btn::before{
  content:'';position:absolute;inset:0;border-radius:14px;
  background:linear-gradient(135deg,var(--primary),var(--primary-light));
  opacity:0;transition:opacity .25s;
}
.provider-btn>*{position:relative;z-index:1}
.provider-btn:hover{border-color:var(--primary-light);transform:translateY(-2px);box-shadow:0 8px 24px rgba(79,70,229,.15)}
.provider-btn.active{
  border-color:var(--primary);
  box-shadow:0 0 0 4px color-mix(in srgb,var(--primary) 15%,transparent),0 8px 32px rgba(79,70,229,.2);
}
.provider-btn.active .provider-name{color:var(--primary)}
.provider-icon{font-size:32px;margin-bottom:10px;display:block}
.provider-name{font-size:16px;font-weight:700;margin-bottom:4px}
.provider-desc{font-size:12px;color:var(--sub)}
.provider-tag{
  display:inline-block;margin-top:8px;padding:3px 10px;border-radius:10px;
  font-size:11px;font-weight:600;
}
.provider-tag.ok{background:color-mix(in srgb,var(--success) 15%,transparent);color:var(--success)}
.provider-tag.warn{background:color-mix(in srgb,var(--danger) 15%,transparent);color:var(--danger)}

.model-chip{
  padding:8px 18px;border:1.5px solid var(--border);border-radius:24px;
  background:var(--card);cursor:pointer;font-size:13px;color:var(--text);
  transition:all .2s;font-weight:500;user-select:none;
}
.model-chip:hover{border-color:var(--primary-light);transform:translateY(-1px);box-shadow:0 4px 12px rgba(79,70,229,.1)}
.model-chip.active{
  border-color:var(--primary);
  background:linear-gradient(135deg,var(--primary),var(--primary-light));
  color:#fff;font-weight:600;box-shadow:0 4px 16px rgba(79,70,229,.35);
}

.settings-select{
  width:100%;padding:11px 14px;border:1.5px solid var(--border);border-radius:12px;
  font-size:14px;background:var(--bg);color:var(--text);outline:none;
  transition:border-color .2s;cursor:pointer;appearance:none;
  background-image:url("data:image/svg+xml,%3Csvg width='12' height='8' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%236b7a99' stroke-width='2' fill='none'/%3E%3C/svg%3E");
  background-repeat:no-repeat;background-position:right 14px center;padding-right:36px;
}
.settings-select:focus{border-color:var(--primary);box-shadow:0 0 0 3px color-mix(in srgb,var(--primary) 15%,transparent)}

.settings-actions{
  display:flex;gap:10px;justify-content:flex-end;padding-top:4px;
  border-top:1px solid var(--border);margin-top:24px;padding-top:20px;
}

.btn-settings{
  padding:10px 24px;border-radius:10px;font-size:14px;font-weight:600;
  cursor:pointer;transition:all .2s;border:none;
}
.btn-settings.cancel{
  background:transparent;border:1.5px solid var(--border);color:var(--sub);
}
.btn-settings.cancel:hover{color:var(--text);border-color:var(--text)}
.btn-settings.save{
  background:linear-gradient(135deg,var(--primary),var(--primary-light));
  color:#fff;box-shadow:0 4px 16px rgba(79,70,229,.3);
}
.btn-settings.save:hover{
  transform:translateY(-1px);box-shadow:0 6px 24px rgba(79,70,229,.4);
}

/* ===== 子知识点左右并排弹窗 ===== */
.sub-split-modal{max-width:1100px;width:95vw}
.sub-split-close{
  background:rgba(255,255,255,.18) !important;
  border-color:rgba(255,255,255,.3) !important;
  color:#fff !important;
}
.sub-split-close:hover{
  background:rgba(239,68,68,.6) !important;
  border-color:rgba(239,68,68,.6) !important;
  color:#fff !important;
}
.sub-split-modal .modal-tools{gap:4px}
.sub-split-modal .modal-close{width:28px;height:28px;font-size:14px}
.sub-split-body{padding:0;overflow:hidden;background:var(--bg)}
.sub-split-columns{
  display:flex;gap:0;min-height:50vh;max-height:70vh;
}
.sub-split-col{
  flex:1;display:flex;flex-direction:column;
  overflow:hidden;background:var(--card);
}
.sub-split-source{
  border-right:1.5px solid var(--border-light);
}
.sub-split-col-head{
  padding:14px 18px;font-size:13px;font-weight:700;
  background:var(--bg);border-bottom:1.5px solid var(--border-light);
  color:var(--text);display:flex;align-items:center;gap:6px;
  flex-shrink:0;letter-spacing:.02em;
}
.sub-split-col-content{
  flex:1;overflow-y:auto;padding:18px;
  font-size:15px;line-height:1.45;color:var(--text);
  white-space:pre-wrap;word-break:break-word;
}
.sub-split-col-content h2{font-size:16px;margin:4px 0 2px;color:var(--primary)}
.sub-split-col-content h3{font-size:15px;margin:4px 0 2px;color:var(--text)}
.sub-split-col-content p{margin:2px 0}
.sub-split-col-content li{margin:2px 0 2px 16px}
.sub-split-col-content blockquote{
  border-left:3px solid var(--primary-light);padding:8px 14px;
  margin:8px 0;background:var(--primary-bg);border-radius:0 8px 8px 0;
  color:var(--sub);
}
.sub-split-empty{
  display:flex;flex-direction:column;align-items:center;justify-content:center;
  flex:1;padding:40px 20px;color:var(--sub);font-size:14px;text-align:center;
}

@media(max-width:768px){
  /* ── 布局 ── */
  .leftbar{display:none}
  .main{padding:8px 12px 96px}
  .layout{flex-direction:column}

  /* ── 导航：玻璃态 ── */
  .nav{
    padding:0 12px;height:56px;
    padding-left:max(12px, env(safe-area-inset-left));
    padding-right:max(12px, env(safe-area-inset-right));
    background:rgba(255,255,255,.85);backdrop-filter:blur(20px);-webkit-backdrop-filter:blur(20px);
    border-bottom:1px solid var(--border-light);
    box-shadow:0 1px 0 rgba(0,0,0,.03);
  }
  [data-dark] .nav{background:rgba(26,23,48,.88)}
  .nav-logo{font-size:18px;font-weight:700}
  .nav-right{gap:4px}

  /* ── 按钮触控优化 ── */
  .btn-icon{width:42px;height:42px;border-radius:12px;font-size:18px}
  .btn-sm{padding:10px 18px;font-size:14px;min-height:42px;border-radius:10px}
  .btn-action{padding:10px 20px;font-size:13px;min-height:42px;border-radius:10px}
  .btn-sub{min-height:38px;padding:8px 14px}
  .btn-upload-main{padding:14px 32px;font-size:16px;border-radius:12px}

  /* ── 表单 ── */
  .form-input{padding:15px 18px;font-size:16px;border-radius:12px;border-width:2px}

  /* ── 弹窗：全屏卡片式 ── */
  .modal{max-width:100vw;width:calc(100vw);margin:0;border-radius:var(--radius-lg) var(--radius-lg) 0 0;max-height:92vh;position:fixed;bottom:0;left:0;right:0;top:auto;animation:slideup-mobile .35s cubic-bezier(.16,1,.3,1)}
  @keyframes slideup-mobile{from{transform:translateY(100%)}to{transform:translateY(0)}}
  .modal-head{padding:16px 18px;border-radius:var(--radius-lg) var(--radius-lg) 0 0}
  .modal-body{padding:18px;max-height:calc(92vh - 64px)}
  .modal-head h3{font-size:16px}
  .modal-tools{gap:4px}
  .modal-tool-btn{width:36px;height:36px;font-size:14px;border-radius:8px}

  /* ── 左右并排弹窗：上下堆叠 ── */
  .sub-split-modal{width:100vw;margin:0;border-radius:var(--radius-lg) var(--radius-lg) 0 0}
  .sub-split-columns{flex-direction:column;min-height:auto;max-height:68vh}
  .sub-split-source{border-right:none;border-bottom:2px solid var(--border-light)}
  .sub-split-col{min-height:25vh}
  .sub-split-col-content{max-height:30vh;font-size:14px;padding:14px}

  /* ── 讲解弹窗 ── */

  /* ── 书籍信息栏：大幅美化 ── */
  .book-bar{
    flex-wrap:wrap;padding:20px 18px;gap:12px;
    background:linear-gradient(135deg,var(--card),var(--card-hover));
    border-radius:var(--radius-lg);border:1px solid var(--border-light);
    margin-bottom:16px;position:relative;overflow:hidden;
  }
  .book-bar::after{
    content:'';position:absolute;top:-40px;right:-40px;
    width:120px;height:120px;border-radius:50%;
    background:linear-gradient(135deg,var(--primary-bg),transparent);
    pointer-events:none;
  }
  .book-icon{font-size:36px}
  .book-name{font-size:17px;font-weight:700}
  .book-meta{font-size:13px}
  .stat-inline{gap:6px;position:relative;z-index:1}
  .stat-pill{padding:6px 12px;font-size:11px;border-radius:14px;font-weight:600}

  /* ── 本页知识点 ── */
  .kp-page-wrap{background:transparent}
  .kp-page-head{
    padding:18px 16px;flex-wrap:wrap;gap:8px;
    background:linear-gradient(135deg,var(--card),var(--card-hover));
    border-radius:var(--radius-lg) var(--radius-lg) 0 0;
    border:1px solid var(--border-light);border-bottom:none;
  }
  .kp-page-head h3{font-size:17px;font-weight:700}
  .kp-chapter-section{
    padding:16px 14px;background:var(--card);
    border:1px solid var(--border-light);border-top:none;
  }
  .kp-chapter-section:last-child{border-radius:0 0 var(--radius-lg) var(--radius-lg);border-bottom:1px solid var(--border-light)}
  .kp-chapter-head{flex-wrap:wrap;gap:8px}
  .kp-chapter-head h3{font-size:15px;font-weight:600}
  .kp-card{padding:14px 14px;border-radius:12px}
  .kp-card-top{flex-wrap:wrap;gap:8px}
  .kp-card-title{font-size:15px;font-weight:600}
  .kp-card-actions{flex-wrap:wrap;gap:8px}
  .kp-card-sub{padding:12px 14px;min-height:48px;border-radius:10px}

  /* ── 书库网格：竖排卡片（像一本书）── */
  .library-grid{grid-template-columns:repeat(2,1fr)!important;gap:12px}
  .library-head{padding:0 4px;margin-bottom:14px}
  .library-head h3{font-size:18px}
  .book-card{display:flex;flex-direction:column;overflow:hidden;border-radius:var(--radius-lg)}
  .book-cover{width:100%;aspect-ratio:200/283;height:auto}
  .book-info{padding:12px 12px 14px}
  .book-title{font-size:14px;font-weight:600;margin-bottom:6px}
  .book-meta{font-size:12px;margin-bottom:8px}
  .book-actions{gap:6px}
  .book-actions .btn-book-action{padding:7px 10px;font-size:12px;min-height:36px;border-radius:8px;font-weight:600}

  /* ── Upload bar ── */
  .upload-bar{flex-direction:column;align-items:flex-start;padding:18px 16px;gap:14px;border-radius:var(--radius-lg)}
  .upload-bar-info{font-size:13px;line-height:1.6}
  .upload-drop{padding:40px 20px;border-radius:14px}
  .upload-drop .upload-icon{font-size:48px}

  /* ── Toast ── */
  .toast{
    top:auto;bottom:90px;right:12px;left:12px;
    max-width:none;padding:16px 20px;border-radius:14px;
    font-size:14px;box-shadow:var(--shadow-lg);
  }
  @keyframes toast-in{from{opacity:0;transform:translateY(30px)}to{opacity:1;transform:translateY(0)}}

  /* ── 加载态 ── */
  .loading-wrap{padding:60px 20px}
  .loading-title{font-size:17px}
  .spinner{width:44px;height:44px;border-width:3px}
  .steps{gap:20px}
  .step{font-size:12px}

  /* ── 空态 ── */
  .empty{padding:48px 16px}
  .empty-icon{font-size:48px}
  .empty h3{font-size:17px}

  /* ── 章节概览 ── */
  .ch-summary{padding:14px 16px;border-radius:0 10px 10px 0}
  .ch-summary-text{font-size:15px;line-height:1.8}

  /* ── 知识树左侧栏 ── */
  .leftbar.expand{width:100vw;position:fixed;z-index:150;top:56px;height:calc(100vh - 56px)}
  .leftbar-drawer{width:100%}
  .sidebar-kp{padding:12px 14px 12px 24px;min-height:48px}
  .sidebar-ch-head{padding:12px 14px;min-height:48px}

  /* ── 章节节点（旧版知识树）── */
  .chapter-head{padding:14px 16px;flex-wrap:wrap;gap:8px;border-radius:10px}
  .ch-title{font-size:15px}
  .kp-head{padding:12px 16px;flex-wrap:wrap;gap:6px}
  .kp-title{font-size:14px}
  .kp-body{padding:10px 16px 16px}
  .kp-summary{font-size:14px}

  /* ── 后台管理 ── */
  .admin-layout{flex-direction:column!important}
  .admin-sidebar{
    width:100%!important;flex-shrink:0;
    display:flex;flex-wrap:nowrap;gap:6px;
    padding:12px 14px!important;border-right:none!important;
    border-bottom:1.5px solid var(--border-light);
    overflow-x:auto;-webkit-overflow-scrolling:touch;
  }
  .admin-sidebar-item{
    padding:10px 18px!important;font-size:13px;
    border-left:none!important;border-radius:12px;
    white-space:nowrap;flex-shrink:0;
    min-height:42px;display:inline-flex!important;
  }
  .admin-sidebar-item.active{
    background:var(--primary-bg)!important;color:var(--primary)!important;
    font-weight:700;
  }
  .admin-main{padding:24px 16px!important}

  /* ── 用户表格 ── */
  .user-table{display:block;overflow-x:auto;-webkit-overflow-scrolling:touch}
  .user-table thead,.user-table tbody{display:table;width:100%;min-width:500px}
  .user-table th,.user-table td{padding:12px 14px;font-size:13px}

  /* ── 设置卡片 ── */
  .setting-card{padding:20px;max-width:none!important;border-radius:var(--radius-lg)}
  .settings-actions{flex-direction:column;gap:10px}
  .btn-settings{padding:14px 20px;font-size:15px;text-align:center;width:100%;border-radius:12px}

  /* ── 登录/注册 ── */
  .auth-page{padding:24px 12px}
  .auth-card{padding:32px 22px;border-radius:var(--radius-lg);box-shadow:var(--shadow-lg)}
  .auth-card h2{font-size:24px}
  .btn-auth{padding:15px;font-size:17px;border-radius:14px}
}

/* ── 小屏手机 ── */
@media(max-width:480px){
  .nav-logo{font-size:16px;font-weight:600}
  .nav{padding:0 10px;gap:6px;height:52px}
  .nav-right{gap:4px}
  .btn-icon{width:38px;height:38px;font-size:16px;border-radius:10px}
  .btn-sm{padding:9px 16px;font-size:13px}
  .kp-card-sub{padding:10px 12px;min-height:46px;gap:6px}
  .book-bar{padding:16px 14px;gap:8px}
  .book-name{font-size:15px}
  .kp-page-head{padding:14px}
  .kp-chapter-section{padding:14px 10px}
  .kp-card{padding:12px 10px}
  .kp-card-title{font-size:14px}
  .kp-card-actions{gap:6px}
  .btn-action{padding:9px 14px;font-size:12px;min-height:40px}
  .library-grid{gap:10px}
  .book-cover{aspect-ratio:200/283;height:auto}
  .book-info{padding:10px 10px 12px}
  .book-title{font-size:13px}
  .modal-head{padding:14px 14px}
  .modal-body{padding:14px}
  .toast{bottom:80px;padding:14px 16px;font-size:13px}
  .ch-summary{padding:10px 12px}
  .ch-summary-text{font-size:14px}
}