*{margin:0;padding:0;box-sizing:border-box}
:root{--bg:#0c0f14;--surface:#141820;--card:#1a1f2a;--card-hover:#1e2533;--border:#2a3040;--text:#e4e8f0;--text-dim:#8892a4;--text-muted:#5c6578;--accent-js:#f0db4f;--accent-py:#4b8bbe;--accent-java:#e76f00;--accent-php:#777bb3;--accent-cs:#68217a;--accent-compare:#10b981;--accent-general:#f59e0b;--accent-extend:#ef4444;--accent-react:#61dafb;--accent-vue:#42b883;--accent-angular:#dd0031;--accent-nextjs:#fff;--accent-django:#0c4b33;--accent-fastapi:#009688;--accent-flask:#000;--accent-spring:#6db33f;--accent-laravel:#ff2d20;--accent-blazor:#512bd4;--accent-efcore:#68217a;--accent-solidity:#363636;--accent-pm:#e67e22;--accent-qa:#9b59b6;--tag-bg:rgba(255,255,255,.06);--tag-border:rgba(255,255,255,.1);--answer-zh-bg:rgba(59,130,246,.06);--answer-en-bg:rgba(16,185,129,.06)}
html{scroll-behavior:smooth;font-size:15px}
body{background:var(--bg);color:var(--text);font-family:'DM Sans','Noto Sans TC',sans-serif;line-height:1.7}

/* Sidebar */
.sidenav{position:fixed;left:0;top:0;width:250px;height:100vh;background:var(--surface);border-right:1px solid var(--border);padding:20px 0;overflow-y:auto;z-index:100}
.sidenav .logo{padding:0 18px;margin-bottom:24px;font-size:1.05rem;font-weight:700}.sidenav .logo span{color:var(--accent-js)}
.sidenav a{display:flex;align-items:center;gap:8px;padding:7px 18px;color:var(--text-dim);text-decoration:none;font-size:.82rem;border-left:3px solid transparent;transition:.2s}
.sidenav a:hover{color:var(--text);background:rgba(255,255,255,.04);border-left-color:var(--text-muted)}
.sidenav .dot{width:8px;height:8px;border-radius:50%;flex-shrink:0}
.sidenav .count{margin-left:auto;font-size:.68rem;color:var(--text-muted);background:var(--tag-bg);padding:2px 6px;border-radius:8px}
.sidenav .search-count{font-size:.62rem;color:#f0db4f;background:rgba(240,219,79,.15);padding:1px 5px;border-radius:6px;margin-left:4px;display:none}

/* Nested sidebar groups */
.sidenav .nav-group{margin-bottom:2px}
.sidenav .nav-group-header{display:flex;align-items:center;gap:8px;padding:7px 18px;color:var(--text-dim);font-size:.82rem;cursor:pointer;border-left:3px solid transparent;transition:.2s;user-select:none}
.sidenav .nav-group-header:hover{color:var(--text);background:rgba(255,255,255,.04);border-left-color:var(--text-muted)}
.sidenav .nav-group-header .arrow{font-size:.6rem;transition:transform .2s;color:var(--text-muted);flex-shrink:0}
.sidenav .nav-group.open .nav-group-header .arrow{transform:rotate(90deg)}
.sidenav .nav-group .nav-children{display:none;padding-left:16px}
.sidenav .nav-group.open .nav-children{display:block}
.sidenav .nav-children a{font-size:.78rem;padding:5px 18px}

/* Main */
.main{margin-left:250px;padding:30px 40px 100px}
.hero{text-align:center;padding:40px 0 30px}
.hero h1{font-size:2rem;font-weight:700;background:linear-gradient(135deg,#f0db4f,#4b8bbe,#e76f00,#777bb3,#68217a,#512bd4);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.hero p{color:var(--text-dim);font-size:.92rem;margin-top:8px}

/* Sticky search bar */
.search-sticky{position:sticky;top:0;z-index:50;background:var(--bg);padding:12px 0 12px;border-bottom:1px solid transparent;transition:border-color .3s}
.search-sticky.scrolled{border-bottom-color:var(--border)}
.search-wrap{max-width:480px;margin:0 auto;position:relative}
.search-wrap input{width:100%;padding:11px 18px 11px 40px;background:var(--card);border:1px solid var(--border);border-radius:10px;color:var(--text);font-size:.9rem;outline:none}
.search-wrap input:focus{border-color:var(--accent-js)}
.search-wrap svg{position:absolute;left:12px;top:50%;transform:translateY(-50%);color:var(--text-muted)}

/* Stats */
.stats{display:flex;gap:10px;justify-content:center;flex-wrap:wrap;margin-bottom:40px}
.stat{background:var(--card);border:1px solid var(--border);border-radius:10px;padding:12px 20px;text-align:center}
.stat .num{font-size:1.4rem;font-weight:700;font-family:'JetBrains Mono',monospace}
.stat .label{font-size:.65rem;color:var(--text-muted);text-transform:uppercase;letter-spacing:.1em}

/* Sections */
.lang-section{margin-bottom:50px}
.section-header{display:flex;align-items:center;gap:14px;padding:14px 0;border-bottom:2px solid var(--border);position:sticky;top:56px;background:var(--bg);z-index:10}
.section-header .icon{width:40px;height:40px;border-radius:10px;display:flex;align-items:center;justify-content:center;font-size:1rem;font-weight:700;flex-shrink:0}
.section-header h2{font-size:1.2rem;font-weight:700}
.section-header .badge{font-size:.72rem;color:var(--text-muted);background:var(--tag-bg);padding:3px 9px;border-radius:8px;margin-left:auto}

/* Controls */
.controls{display:flex;gap:8px;margin:12px 0 16px}
.controls button{background:var(--tag-bg);border:1px solid var(--tag-border);color:var(--text-dim);padding:5px 12px;border-radius:7px;cursor:pointer;font-size:.75rem;transition:.2s}
.controls button:hover{background:rgba(255,255,255,.1);color:var(--text)}

/* QA Cards */
.qa-card{background:var(--card);border:1px solid var(--border);border-radius:12px;margin-bottom:10px;overflow:hidden;transition:.2s}
.qa-card:hover{border-color:rgba(255,255,255,.12)}
.qa-header{padding:14px 16px;cursor:pointer;display:flex;align-items:flex-start;gap:12px}
.qa-num,.qa-toggle{user-select:none}
.qa-num{font-family:'JetBrains Mono',monospace;font-size:.72rem;color:var(--text-muted);background:var(--tag-bg);padding:3px 7px;border-radius:5px;flex-shrink:0;margin-top:2px}
.qa-q{flex:1}
.qa-q .zh{font-weight:600;font-size:.9rem;line-height:1.5;font-family:'Noto Sans TC','DM Sans',sans-serif}
.qa-q .en{color:var(--text);font-size:.82rem;margin-top:2px;opacity:.75}
.qa-toggle{color:var(--text-muted);font-size:1rem;flex-shrink:0;transition:transform .3s;margin-top:2px}
.qa-card.open .qa-toggle{transform:rotate(180deg)}

/* QA Answers */
.qa-answer{display:none;padding:0 16px 16px;padding-left:50px}
.qa-card.open .qa-answer{display:block}
.ans-block{border-radius:8px;padding:12px 14px;margin-bottom:8px;font-size:.84rem;line-height:1.7}
.ans-block.zh{background:var(--answer-zh-bg);border-left:3px solid rgba(59,130,246,.4);font-family:'Noto Sans TC','DM Sans',sans-serif}
.ans-block.en{background:var(--answer-en-bg);border-left:3px solid rgba(16,185,129,.4)}
.ans-block .tag{font-size:.62rem;text-transform:uppercase;letter-spacing:.1em;color:var(--text-muted);margin-bottom:4px;font-weight:600}
.ans-block code{font-family:'JetBrains Mono',monospace;font-size:.78rem;background:rgba(255,255,255,.08);padding:1px 5px;border-radius:3px}
.ans-block strong{color:var(--text)}

/* Structured answer content */
.ans-block p{margin-bottom:8px}
.ans-block p:last-child{margin-bottom:0}
.ans-block ul,.ans-block ol{margin:8px 0 8px 20px}
.ans-block li{margin-bottom:4px}
.ans-block li::marker{color:var(--text-muted)}

/* Code blocks */
.ans-block pre{background:#1a1b2e;border:1px solid rgba(255,255,255,.08);border-radius:8px;padding:14px;margin:10px 0;overflow-x:auto;line-height:1.6}
.ans-block pre code{background:none;padding:0;font-size:.78rem;color:#c9d1d9;display:block;white-space:pre}
.ans-block pre code.hljs{background:#1a1b2e;padding:0}

/* SVG diagrams */
.qa-diagram{width:100%;max-width:600px;margin:12px auto;display:block;border-radius:8px;background:rgba(255,255,255,.03);padding:16px}
.qa-diagram text{fill:var(--text);font-family:'DM Sans','Noto Sans TC',sans-serif;font-size:12px}
.qa-diagram .node-rect{fill:var(--card);stroke:var(--border);rx:6}
.qa-diagram .node-text{fill:var(--text);text-anchor:middle;dominant-baseline:central}
.qa-diagram .arrow{stroke:var(--text-muted);fill:none;stroke-width:1.5}
.qa-diagram .label{fill:var(--text-dim);font-size:10px}

/* Search highlight */
mark{background:rgba(240,219,79,.35);color:var(--text);padding:0 2px;border-radius:2px}

/* Back to top */
.back-to-top{position:fixed;bottom:30px;right:30px;width:44px;height:44px;border-radius:50%;background:var(--surface);border:1px solid var(--border);color:var(--text-dim);font-size:1.2rem;cursor:pointer;display:none;align-items:center;justify-content:center;z-index:200;transition:.2s;box-shadow:0 4px 12px rgba(0,0,0,.3)}
.back-to-top:hover{background:var(--card);color:var(--text);border-color:var(--accent-js)}

/* Search result count */
.search-result-count{text-align:center;color:var(--text-muted);font-size:.82rem;margin-bottom:16px;display:none}

/* Responsive */
@media(max-width:900px){
  .sidenav{display:none}
  .main{margin-left:0;padding:16px 12px 80px}
  .hero h1{font-size:1.4rem}
  .qa-answer{padding-left:16px}
  .section-header{top:56px}
}