@import url('https://fonts.googleapis.com/css2?family=Noto+Serif+SC:wght@500;700;900&family=Noto+Sans+SC:wght@400;500;700&family=JetBrains+Mono:wght@400;600&display=swap');

:root{
  --brass:#c9952c; --brass-soft:#e3b65a; --brass-bg:rgba(201,149,44,0.10);
  --rust:#c1543a; --rust-soft:#d4755e;
  --teal:#2f8a76; --teal-soft:#4db8a0;
  --paper:#f6f1e4; --paper-card:#fffdf6; --paper-soft:#efe8d4;
  --text-dark:#20242c; --text-dark-dim:#5b5a4f; --text-dark-faint:#8a8472;
  --line:rgba(60,40,10,0.10);
  --line-strong:rgba(60,40,10,0.18);
  --shadow:0 8px 24px rgba(60,40,10,.10);
}
*{box-sizing:border-box;margin:0;padding:0;}
html,body{height:100%;overflow:hidden;font-family:'Noto Sans SC',sans-serif;color:var(--text-dark);background:var(--paper);}
code,.mono{font-family:'JetBrains Mono','Noto Sans SC',monospace;}
h1,h2,h3,.serif{font-family:'Noto Serif SC',serif;}
a{color:inherit;text-decoration:none;}

/* ========== 整体布局 ========== */
.roadmap-app{display:flex;height:100vh;width:100vw;overflow:hidden;}

/* ========== 左侧目录 ========== */
.sidebar{
  width:300px;flex-shrink:0;background:#2a2d35;
  border-right:1px solid rgba(255,255,255,.08);
  display:flex;flex-direction:column;
  transition:width .3s ease,transform .3s ease;
  overflow:hidden;z-index:40;
}
.sidebar.collapsed{width:0;border-right:none;}

.sidebar-header{
  display:flex;align-items:center;justify-content:space-between;
  padding:14px 16px;border-bottom:1px solid rgba(255,255,255,.08);flex-shrink:0;
}
.sidebar-header .brand{display:flex;align-items:center;gap:8px;}
.sidebar-header .brand .logo{font-size:18px;}
.sidebar-header .brand .name{font-family:'Noto Serif SC',serif;font-size:14px;font-weight:700;color:#ece7da;}
.sidebar-header .brand .name b{color:var(--brass-soft);}
.sidebar-header .collapse-btn{
  width:32px;height:32px;border-radius:6px;border:1px solid rgba(255,255,255,.12);
  background:rgba(255,255,255,.06);color:#ece7da;cursor:pointer;
  display:flex;align-items:center;justify-content:center;font-size:16px;font-weight:700;
  transition:all .2s ease;
}
.sidebar-header .collapse-btn:hover{background:rgba(201,149,44,.2);border-color:var(--brass);}

/* 全部折叠按钮 */
.sidebar-actions{padding:8px 16px;border-bottom:1px solid rgba(255,255,255,.08);display:flex;justify-content:flex-end;gap:8px;flex-shrink:0;}
.sidebar-actions button{
  font-size:12px;color:rgba(236,231,218,.5);background:none;border:none;cursor:pointer;
  padding:4px 8px;border-radius:4px;transition:color .2s ease;
}
.sidebar-actions button:hover{color:var(--brass-soft);}

/* 目录列表 */
.sidebar-toc{flex:1;overflow-y:auto;overflow-x:hidden;padding:8px 0;}
.sidebar-toc::-webkit-scrollbar{width:4px;}
.sidebar-toc::-webkit-scrollbar-thumb{background:rgba(255,255,255,.15);border-radius:2px;}

/* 章节（一级） */
.chapter-group{margin-bottom:2px;}
.chapter-header{
  display:flex;align-items:center;gap:8px;padding:12px 16px;
  cursor:pointer;font-size:14px;font-weight:600;color:#ece7da;
  transition:background .15s ease;user-select:none;
}
.chapter-header:hover{background:rgba(255,255,255,.05);}
.chapter-header .arrow{
  width:16px;height:16px;display:flex;align-items:center;justify-content:center;
  font-size:11px;color:rgba(236,231,218,.4);transition:transform .2s ease;flex-shrink:0;
}
.chapter-group.open > .chapter-header .arrow{transform:rotate(90deg);}
.chapter-header .ch-num{
  font-size:11px;font-weight:600;padding:2px 8px;border-radius:10px;
  flex-shrink:0;letter-spacing:.02em;
  background:rgba(201,149,44,.15);color:var(--brass-soft);
}
.chapter-header .ch-title{flex:1;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;}
.chapter-header .ch-badge{
  font-size:10px;padding:2px 8px;border-radius:10px;font-weight:600;flex-shrink:0;
}
.chapter-header .ch-dot{display:none;}

/* 篇章配色 - 保留用于左侧边条等 */
.ch-onboarding .ch-dot{background:var(--teal);}
.ch-foundations .ch-dot{background:var(--teal);}
.ch-core .ch-dot{background:var(--brass);}
.ch-abstractions .ch-dot{background:var(--rust);}
.ch-collections .ch-dot{background:var(--teal);}
.ch-memory .ch-dot{background:var(--rust);}
.ch-concurrency .ch-dot{background:#8b5cf6;}
.ch-async .ch-dot{background:#8b5cf6;}
.ch-engineering .ch-dot{background:var(--rust);}

/* 状态徽章 */
.badge-done{background:rgba(47,138,118,.2);color:var(--teal-soft);}
.badge-soon{background:rgba(201,149,44,.2);color:var(--brass-soft);}
.badge-plan{background:rgba(255,255,255,.06);color:rgba(236,231,218,.4);}

/* 知识点（二级） */
.chapter-items{
  max-height:0;overflow:hidden;
  transition:max-height .3s ease;
}
.chapter-group.open > .chapter-items{max-height:2000px;}
.toc-item{
  display:flex;align-items:center;gap:8px;
  padding:10px 16px 10px 40px;
  font-size:14px;color:rgba(236,231,218,.7);
  cursor:pointer;transition:all .15s ease;
  border-left:3px solid transparent;
}
.toc-item:hover{background:rgba(255,255,255,.05);color:#ece7da;}
.toc-item.active{
  background:rgba(201,149,44,.15);color:var(--brass-soft);
  border-left-color:var(--brass-soft);font-weight:600;
}
.toc-item .item-icon{font-size:16px;flex-shrink:0;}
.toc-item .item-name{flex:1;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;}
.toc-item .item-diff{font-size:11px;color:rgba(236,231,218,.35);flex-shrink:0;letter-spacing:1px;}

/* ========== 右侧内容区 ========== */
.content{flex:1;min-width:0;display:flex;flex-direction:column;height:100%;overflow:hidden;}

/* 顶栏 */
.content-topbar{
  flex-shrink:0;height:50px;display:flex;align-items:center;
  padding:0 24px;border-bottom:1px solid var(--line);
  background:rgba(246,241,228,0.92);backdrop-filter:blur(6px);
  font-size:13px;
}
.content-topbar .expand-btn{
  width:32px;height:32px;border-radius:6px;border:1px solid var(--line);
  background:var(--paper-card);color:var(--text-dark-dim);cursor:pointer;
  display:none;align-items:center;justify-content:center;font-size:14px;
  margin-right:14px;transition:all .2s ease;
}
.content-topbar .expand-btn:hover{background:var(--brass-bg);border-color:var(--brass);}
.sidebar.collapsed ~ .content .content-topbar .expand-btn{display:flex;}
.content-topbar .breadcrumb{color:var(--text-dark-faint);font-size:12px;}
.content-topbar .breadcrumb span{color:var(--brass);}
.content-topbar .topbar-right{margin-left:auto;display:flex;align-items:center;gap:12px;}
.content-topbar .pill{
  padding:3px 10px;border-radius:20px;
  background:rgba(201,149,44,0.12);color:var(--brass);font-size:11px;font-weight:600;
}

/* 内容滚动区 */
.content-body{flex:1;overflow-y:auto;padding:40px 48px 80px;}
.content-body::-webkit-scrollbar{width:6px;}
.content-body::-webkit-scrollbar-thumb{background:rgba(60,40,10,.12);border-radius:3px;}

/* 嵌入式课程（直接渲染 PPT） */
.content-body.has-lesson{padding:0;overflow:hidden;display:flex;flex-direction:column;}
.lesson-loading{text-align:center;padding:60px 20px;color:var(--text-dark-dim);font-size:14px;}
.lesson-inline-container{display:flex;flex-direction:column;flex:1;min-height:0;overflow:hidden;}
.lesson-bottom-nav{flex-shrink:0;padding:8px 48px;border-top:1px solid var(--line);background:var(--paper-card);}
.lesson-bottom-nav .bottom-nav{max-width:860px;margin:0 auto;}
.lesson-inline-container .lesson-topbar{
  flex-shrink:0;display:flex;align-items:center;justify-content:space-between;
  padding:10px 24px;border-bottom:1px solid var(--line);background:var(--paper-card);
}
.lesson-inline-container .lesson-title{font-weight:700;font-size:14px;color:var(--text-dark);}
.lesson-inline-container .lesson-meta{display:flex;align-items:center;gap:10px;font-size:12px;color:var(--text-dark-dim);}
.lesson-inline-container .lesson-meta .pill{
  padding:2px 10px;border-radius:20px;background:rgba(201,149,44,.12);color:var(--brass);font-size:11px;font-weight:600;
}
.lesson-viewport-wrap{flex:1;display:flex;flex-direction:column;overflow:hidden;min-height:0;}
.lesson-viewport-wrap .deck-viewport{flex:1;position:relative;overflow:hidden;cursor:pointer;min-height:0;}
.lesson-viewport-wrap .deck{position:absolute;top:0;left:0;width:100%;height:100%;display:flex;transition:transform .35s cubic-bezier(.65,0,.35,1);will-change:transform;}
.lesson-viewport-wrap .slide{flex:0 0 100%;height:100%;display:flex;flex-direction:column;align-items:center;justify-content:flex-start;padding:48px 6vw 60px;overflow-x:hidden;overflow-y:auto;}
.lesson-viewport-wrap .deck-viewport .arrow-btn{
  position:absolute;top:50%;transform:translateY(-50%);
  width:40px;height:40px;border-radius:50%;border:1px solid var(--line);
  background:var(--paper-card);color:var(--text-dark-dim);cursor:pointer;
  font-size:20px;display:flex;align-items:center;justify-content:center;
  z-index:20;transition:all .2s ease;box-shadow:0 4px 12px rgba(60,40,10,.08);
}
.lesson-viewport-wrap .deck-viewport .arrow-btn:hover{border-color:var(--brass);color:var(--brass);}
.lesson-viewport-wrap .deck-viewport .arrow-btn.prev{left:12px;}
.lesson-viewport-wrap .deck-viewport .arrow-btn.next{right:12px;}
.lesson-viewport-wrap .deck-viewport .arrow-btn:disabled{opacity:.25;cursor:default;}
.lesson-viewport-wrap .deck-viewport .controls{
  position:absolute;bottom:0;left:0;right:0;height:50px;z-index:20;
  display:flex;align-items:center;justify-content:center;gap:8px;
  background:linear-gradient(to top,rgba(246,241,228,.9),transparent);pointer-events:none;
}
.lesson-viewport-wrap .deck-viewport .controls .dot{
  pointer-events:auto;width:8px;height:8px;border-radius:50%;background:rgba(60,40,10,.2);cursor:pointer;transition:all .25s ease;
}
.lesson-viewport-wrap .deck-viewport .controls .dot.active{background:var(--brass);width:20px;border-radius:6px;}

/* 点击左右区域翻页的视觉提示 */
.lesson-viewport-wrap .deck-viewport::before,
.lesson-viewport-wrap .deck-viewport::after{
  content:'';position:absolute;top:0;bottom:50px;width:25%;z-index:15;
  pointer-events:none;opacity:0;transition:opacity .2s ease;
}
.lesson-viewport-wrap .deck-viewport::before{left:0;background:linear-gradient(to right,rgba(201,149,44,.06),transparent);}
.lesson-viewport-wrap .deck-viewport::after{right:0;background:linear-gradient(to left,rgba(201,149,44,.06),transparent);}
.lesson-viewport-wrap .deck-viewport:hover::before,
.lesson-viewport-wrap .deck-viewport:hover::after{opacity:1;}

/* 嵌入 PPT 内容字号放大 */
.lesson-viewport-wrap .eyebrow{font-size:14px;letter-spacing:.15em;margin-bottom:16px;}
.lesson-viewport-wrap .big{font-size:clamp(22px,3vw,36px);line-height:1.3;margin-bottom:14px;}
.lesson-viewport-wrap .sub{font-size:clamp(15px,1.6vw,19px);line-height:1.7;}
.lesson-viewport-wrap .emblem{width:80px;height:80px;font-size:52px;margin-bottom:18px;}
.lesson-viewport-wrap .codebox{font-size:13px;line-height:1.75;padding:16px 20px;}
.lesson-viewport-wrap .card{padding:20px;width:220px;}
.lesson-viewport-wrap .card h4{font-size:15px;}
.lesson-viewport-wrap .card p{font-size:13px;}
.lesson-viewport-wrap .card .ic{font-size:28px;}
.lesson-viewport-wrap .map-grid .life,
.lesson-viewport-wrap .map-grid .rust{font-size:15px;}
.lesson-viewport-wrap .sumlist li{font-size:15px;padding:12px 0 12px 30px;}
.lesson-viewport-wrap .mantra{font-size:16px;padding:18px 26px;}
.lesson-viewport-wrap .mis p{font-size:13.5px;}
.lesson-viewport-wrap .transfer-btn{font-size:14px;padding:12px 28px;}
.lesson-viewport-wrap .transfer-note{font-size:13px;}
.lesson-viewport-wrap .title-foot{font-size:13px;}

/* 内容卡片 */
.content-inner{max-width:860px;margin:0 auto;}
.content-inner h1{
  font-size:clamp(24px,3vw,34px);font-weight:700;margin-bottom:8px;color:var(--text-dark);
}
.content-inner .subtitle{font-size:15px;color:var(--text-dark-dim);margin-bottom:28px;line-height:1.7;}
.content-inner .meta-row{display:flex;gap:16px;margin-bottom:32px;flex-wrap:wrap;}
.content-inner .meta-tag{
  font-size:12px;padding:5px 14px;border-radius:20px;
  background:var(--paper-card);border:1px solid var(--line);color:var(--text-dark-dim);
}

/* 知识点列表 */
.kp-list{display:flex;flex-direction:column;gap:12px;}
.kp-card{
  display:flex;align-items:center;gap:16px;
  background:var(--paper-card);border-radius:12px;padding:18px 22px;
  border:1px solid var(--line);box-shadow:0 2px 8px rgba(60,40,10,.04);
  cursor:pointer;transition:all .2s ease;
}
.kp-card:hover{border-color:rgba(201,149,44,.4);box-shadow:var(--shadow);transform:translateY(-2px);}
.kp-card .kp-icon{font-size:28px;flex-shrink:0;}
.kp-card .kp-info{flex:1;min-width:0;}
.kp-card .kp-name{font-size:15px;font-weight:700;font-family:'Noto Serif SC',serif;color:var(--text-dark);margin-bottom:2px;}
.kp-card .kp-en{font-size:11px;color:var(--text-dark-faint);font-family:'JetBrains Mono',monospace;}
.kp-card .kp-analogy{
  font-size:12px;color:var(--brass);background:rgba(201,149,44,.08);
  padding:3px 10px;border-radius:12px;white-space:nowrap;
}
.kp-card .kp-status{
  font-size:10px;padding:3px 9px;border-radius:12px;font-weight:600;flex-shrink:0;
}
.kp-card .kp-diff{font-size:11px;color:var(--text-dark-faint);letter-spacing:1px;flex-shrink:0;}

/* 空状态 */
.empty-state{
  text-align:center;padding:80px 20px;color:var(--text-dark-dim);
}
.empty-state .empty-icon{font-size:48px;margin-bottom:16px;opacity:.6;}
.empty-state p{font-size:14px;line-height:1.8;}

/* 章节描述 */
.chapter-desc{
  background:var(--paper-card);border-radius:12px;padding:20px 24px;
  border:1px solid var(--line);margin-bottom:24px;
  font-size:14px;color:var(--text-dark-dim);line-height:1.8;
}
.chapter-desc .desc-icon{font-size:18px;margin-right:8px;}

/* 底部导航 */
.bottom-nav{
  display:flex;justify-content:space-between;margin-top:40px;
  padding-top:24px;border-top:1px solid var(--line);
}
.bottom-nav .nav-btn{
  display:flex;align-items:center;gap:8px;
  padding:10px 20px;border-radius:10px;
  background:var(--paper-card);border:1px solid var(--line);
  font-size:13px;color:var(--text-dark-dim);cursor:pointer;
  transition:all .2s ease;
}
.bottom-nav .nav-btn:hover{border-color:var(--brass);color:var(--brass);}
.bottom-nav .nav-btn.disabled{opacity:.4;cursor:default;}
.bottom-nav .nav-btn.disabled:hover{border-color:var(--line);color:var(--text-dark-dim);}

/* ========== 响应式 ========== */
@media (max-width:760px){
  .sidebar{position:fixed;top:0;left:0;bottom:0;width:280px;transform:translateX(-100%);
    box-shadow:0 0 30px rgba(0,0,0,.15);z-index:50;}
  .sidebar:not(.collapsed){transform:translateX(0);}
  .sidebar.collapsed{width:280px;}
  .content-topbar .expand-btn{display:flex !important;}
  .content-body{padding:24px 20px 60px;}
  .kp-card{flex-wrap:wrap;}
  .lesson-viewport-wrap .slide{padding:24px 4vw 40px;}
  .lesson-viewport-wrap .deck-viewport .arrow-btn{width:32px;height:32px;font-size:16px;}
  .lesson-bottom-nav{padding:6px 20px;}
}
@media (prefers-reduced-motion:reduce){
  *{transition-duration:.01ms !important;animation-duration:.01ms !important;}
}