:root{--bg-primary: #0f1117;--bg-secondary: #1a1d29;--bg-card: #222639;--bg-hover: #2a2f45;--text-primary: #e8eaed;--text-secondary: #9aa0b2;--text-muted: #6b7280;--accent-blue: #3b82f6;--accent-green: #10b981;--accent-red: #ef4444;--accent-yellow: #f59e0b;--accent-purple: #8b5cf6;--border: #2d3348;--radius: 8px}*{margin:0;padding:0;box-sizing:border-box}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif;background:var(--bg-primary);color:var(--text-primary);line-height:1.6}a{color:var(--accent-blue);text-decoration:none}a:hover{text-decoration:underline}.app-layout{display:flex;min-height:100vh}.sidebar{width:240px;background:var(--bg-secondary);border-right:1px solid var(--border);padding:20px 0;position:fixed;top:0;left:0;bottom:0;overflow-y:auto}.sidebar-logo{padding:0 20px 20px;border-bottom:1px solid var(--border);margin-bottom:10px}.sidebar-logo h1{font-size:18px;font-weight:700;background:linear-gradient(135deg,var(--accent-blue),var(--accent-purple));-webkit-background-clip:text;-webkit-text-fill-color:transparent}.sidebar-logo p{font-size:11px;color:var(--text-muted);margin-top:2px}.sidebar nav{padding:0 8px}.sidebar nav a{display:flex;align-items:center;gap:10px;padding:10px 12px;border-radius:var(--radius);color:var(--text-secondary);font-size:14px;transition:all .15s;text-decoration:none}.sidebar nav a:hover,.sidebar nav a.active{background:var(--bg-hover);color:var(--text-primary)}.sidebar nav a.active{background:#3b82f626;color:var(--accent-blue)}.main-content{flex:1;margin-left:240px;padding:32px 40px;max-width:1200px}.page-header{margin-bottom:32px}.page-header h2{font-size:28px;font-weight:700;margin-bottom:6px}.page-header p{color:var(--text-secondary);font-size:15px}.card-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(320px,1fr));gap:16px}.card{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);padding:20px;transition:all .15s;cursor:pointer}.card:hover{border-color:var(--accent-blue);transform:translateY(-2px);box-shadow:0 4px 12px #0000004d}.card h3{font-size:16px;font-weight:600;margin-bottom:8px}.card p{font-size:13px;color:var(--text-secondary);margin-bottom:12px}.card-meta{display:flex;gap:8px;flex-wrap:wrap}.badge{display:inline-block;padding:2px 8px;border-radius:4px;font-size:11px;font-weight:600;text-transform:uppercase;letter-spacing:.5px}.badge-blue{background:#3b82f633;color:var(--accent-blue)}.badge-green{background:#10b98133;color:var(--accent-green)}.badge-red{background:#ef444433;color:var(--accent-red)}.badge-yellow{background:#f59e0b33;color:var(--accent-yellow)}.badge-purple{background:#8b5cf633;color:var(--accent-purple)}.filters-bar{display:flex;gap:12px;margin-bottom:24px;flex-wrap:wrap;align-items:center}.filters-bar select,.filters-bar input{background:var(--bg-card);border:1px solid var(--border);color:var(--text-primary);padding:8px 12px;border-radius:var(--radius);font-size:13px;outline:none}.filters-bar select:focus,.filters-bar input:focus{border-color:var(--accent-blue)}.detail-page{max-width:800px}.detail-page h2{font-size:24px;margin-bottom:6px}.detail-page .meta-row{display:flex;gap:10px;margin-bottom:20px;flex-wrap:wrap}.detail-section{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);padding:20px;margin-bottom:16px}.detail-section h4{font-size:14px;color:var(--text-muted);text-transform:uppercase;letter-spacing:.5px;margin-bottom:10px}.detail-section p,.detail-section div{font-size:14px;line-height:1.7}.stats-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:12px;margin-bottom:20px}.stat-card{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);padding:16px;text-align:center}.stat-card .stat-value{font-size:28px;font-weight:700;color:var(--accent-blue)}.stat-card .stat-label{font-size:12px;color:var(--text-muted);margin-top:4px}.btn{padding:8px 16px;border:none;border-radius:var(--radius);font-size:14px;font-weight:500;cursor:pointer;transition:all .15s}.btn-primary{background:var(--accent-blue);color:#fff}.btn-primary:hover{background:#2563eb}.btn-secondary{background:var(--bg-card);color:var(--text-primary);border:1px solid var(--border)}.btn-secondary:hover{background:var(--bg-hover)}.btn-success{background:var(--accent-green);color:#fff}.quiz-question{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);padding:20px;margin-bottom:16px}.quiz-question h4{font-size:15px;margin-bottom:12px}.quiz-option{display:block;width:100%;text-align:left;padding:10px 14px;margin-bottom:6px;background:var(--bg-secondary);border:1px solid var(--border);border-radius:var(--radius);color:var(--text-primary);font-size:14px;cursor:pointer;transition:all .15s}.quiz-option:hover{border-color:var(--accent-blue)}.quiz-option.selected{border-color:var(--accent-blue);background:#3b82f626}.quiz-option.correct{border-color:var(--accent-green);background:#10b98126}.quiz-option.incorrect{border-color:var(--accent-red);background:#ef444426}.quiz-explanation{margin-top:8px;padding:10px;background:#3b82f61a;border-radius:var(--radius);font-size:13px;color:var(--text-secondary)}.viz-controls{display:grid;grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:12px;margin-bottom:20px}.viz-controls label{display:flex;flex-direction:column;gap:4px;font-size:13px;color:var(--text-secondary)}.viz-controls input,.viz-controls select{background:var(--bg-card);border:1px solid var(--border);color:var(--text-primary);padding:8px 12px;border-radius:var(--radius);font-size:14px}.legs-list{display:flex;flex-direction:column;gap:8px;margin-bottom:16px}.leg-row{display:flex;gap:8px;align-items:center;flex-wrap:wrap}.leg-row select,.leg-row input{background:var(--bg-card);border:1px solid var(--border);color:var(--text-primary);padding:6px 10px;border-radius:var(--radius);font-size:13px}.glossary-list{display:flex;flex-direction:column;gap:2px}.glossary-item{padding:12px 16px;background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);cursor:pointer;transition:all .15s}.glossary-item:hover{border-color:var(--accent-blue)}.glossary-item .term-name{font-weight:600;font-size:15px;margin-bottom:4px}.glossary-item .term-def{font-size:13px;color:var(--text-secondary)}.glossary-item .term-cat{font-size:11px;color:var(--text-muted);margin-top:4px}.lesson-content{font-size:15px;line-height:1.8}.lesson-content h2{font-size:22px;margin:24px 0 12px}.lesson-content h3{font-size:18px;margin:20px 0 10px;color:var(--accent-blue)}.lesson-content h4{font-size:15px;margin:16px 0 8px}.lesson-content p{margin-bottom:12px}.lesson-content table{width:100%;border-collapse:collapse;margin:16px 0}.lesson-content th,.lesson-content td{padding:8px 12px;border:1px solid var(--border);text-align:left;font-size:14px}.lesson-content th{background:var(--bg-card);font-weight:600}.lesson-content code{background:var(--bg-card);padding:2px 6px;border-radius:4px;font-size:13px}.progress-bar{height:8px;background:var(--bg-card);border-radius:4px;overflow:hidden}.progress-bar-fill{height:100%;background:linear-gradient(90deg,var(--accent-blue),var(--accent-green));border-radius:4px;transition:width .3s}.back-link{display:inline-flex;align-items:center;gap:6px;color:var(--text-secondary);font-size:14px;margin-bottom:20px;cursor:pointer}.back-link:hover{color:var(--text-primary);text-decoration:none}@media(max-width:768px){.sidebar{display:none}.main-content{margin-left:0;padding:20px}.card-grid{grid-template-columns:1fr}}