:root{--bg: #0b0f19;--bg-elevated: #111827;--bg-card: #161f32;--bg-hover: #1e293b;--border: #263248;--text: #f1f5f9;--text-muted: #94a3b8;--text-dim: #64748b;--accent-fin: #10b981;--accent-ai: #6366f1;--accent: #38bdf8;--success: #22c55e;--warning: #f59e0b;--danger: #ef4444;--radius: 12px;--font-sans: "Inter", -apple-system, BlinkMacSystemFont, sans-serif;--font-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, monospace}*{box-sizing:border-box;margin:0;padding:0}body{font-family:var(--font-sans);background:var(--bg);color:var(--text);line-height:1.6;-webkit-font-smoothing:antialiased}a{color:var(--accent);text-decoration:none}a:hover{text-decoration:underline}button{font-family:inherit;cursor:pointer}.app-shell{display:flex;min-height:100vh}.sidebar{width:300px;flex-shrink:0;background:var(--bg-elevated);border-right:1px solid var(--border);display:flex;flex-direction:column;position:sticky;top:0;height:100vh;overflow-y:auto}.brand{padding:20px;border-bottom:1px solid var(--border)}.brand-title{font-size:1.1rem;font-weight:800;letter-spacing:-.02em;display:flex;align-items:center;gap:8px}.brand-sub{font-size:.78rem;color:var(--text-muted);margin-top:4px}.progress-box{padding:14px 20px;border-bottom:1px solid var(--border)}.progress-row{display:flex;justify-content:space-between;font-size:.8rem;color:var(--text-muted);margin-bottom:6px}.progress-bar{height:7px;background:var(--bg);border-radius:999px;overflow:hidden}.progress-fill{height:100%;background:linear-gradient(90deg,var(--accent-fin),var(--accent));transition:width .3s ease}.nav-section{padding:14px 12px}.nav-label{font-size:.7rem;font-weight:700;text-transform:uppercase;letter-spacing:.08em;color:var(--text-dim);padding:0 8px 8px}.nav-btn{width:100%;display:flex;align-items:center;gap:10px;padding:9px 10px;border-radius:8px;border:none;background:transparent;color:var(--text-muted);font-size:.88rem;font-weight:500;text-align:left;transition:background .15s,color .15s}.nav-btn:hover{background:var(--bg-hover);color:var(--text)}.nav-btn.active{background:#38bdf824;color:var(--accent)}.lesson-nav-item{width:100%;display:flex;align-items:flex-start;gap:8px;padding:8px 10px;border-radius:8px;border:none;background:transparent;color:var(--text-muted);text-align:left;font-size:.82rem;margin-bottom:2px}.lesson-nav-item:hover{background:var(--bg-hover);color:var(--text)}.lesson-nav-item.active{background:var(--bg-card);color:var(--text);border:1px solid var(--border)}.level-dot{width:8px;height:8px;border-radius:999px;margin-top:6px;flex-shrink:0}.main{flex:1;min-width:0;padding:28px 36px 64px;max-width:1080px;margin:0 auto}.topbar{display:flex;flex-wrap:wrap;gap:12px;align-items:center;justify-content:space-between;margin-bottom:24px}.search-wrap{position:relative;flex:1;min-width:240px;max-width:420px}.search-icon{position:absolute;left:12px;top:50%;transform:translateY(-50%);color:var(--text-dim)}.search-input{width:100%;background:var(--bg-elevated);border:1px solid var(--border);border-radius:10px;padding:9px 12px 9px 36px;color:var(--text);font-size:.9rem;outline:none}.search-input:focus{border-color:var(--accent)}.filter-pills{display:flex;gap:8px;flex-wrap:wrap}.pill{padding:7px 14px;border-radius:999px;border:1px solid var(--border);background:var(--bg-elevated);color:var(--text-muted);font-size:.82rem;font-weight:600}.pill.active{border-color:var(--accent);background:#38bdf824;color:var(--accent)}.hero{background:linear-gradient(135deg,#10b9811f,#6366f124);border:1px solid var(--border);border-radius:16px;padding:24px 28px;margin-bottom:28px}.hero h1{font-size:1.65rem;font-weight:800;letter-spacing:-.02em;margin-bottom:8px}.hero p{color:var(--text-muted);font-size:.95rem;max-width:720px}.stats-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:12px;margin-top:18px}.stat-card{background:#0b0f198c;border:1px solid var(--border);border-radius:10px;padding:12px 14px}.stat-val{font-size:1.3rem;font-weight:800}.stat-lbl{font-size:.78rem;color:var(--text-muted)}.track-header{display:flex;align-items:center;justify-content:space-between;margin:26px 0 12px}.track-badge{display:inline-flex;align-items:center;gap:6px;font-size:.75rem;font-weight:700;text-transform:uppercase;letter-spacing:.06em;padding:4px 10px;border-radius:999px}.track-badge.financial{background:#10b98124;color:var(--accent-fin)}.track-badge.edge-ai{background:#6366f12e;color:#a5b4fc}.cards-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:14px}.lesson-card{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);padding:18px;display:flex;flex-direction:column;gap:10px;transition:transform .15s,border-color .15s;cursor:pointer}.lesson-card:hover{transform:translateY(-2px);border-color:var(--accent)}.card-top{display:flex;justify-content:space-between;align-items:center;gap:8px}.level-tag{font-size:.74rem;font-weight:700;padding:3px 9px;border-radius:999px;background:#ffffff0f}.lesson-card h3{font-size:1.02rem;font-weight:700;line-height:1.35}.lesson-card p{font-size:.85rem;color:var(--text-muted);flex:1}.card-meta{display:flex;gap:12px;font-size:.78rem;color:var(--text-dim);padding-top:8px;border-top:1px solid var(--border)}.back-btn{display:inline-flex;align-items:center;gap:6px;background:var(--bg-elevated);border:1px solid var(--border);color:var(--text);padding:7px 14px;border-radius:8px;font-size:.85rem;font-weight:600}.lesson-header{margin:18px 0 24px;padding-bottom:20px;border-bottom:1px solid var(--border)}.lesson-header h1{font-size:1.85rem;font-weight:800;letter-spacing:-.02em;margin:10px 0}.complete-btn{display:inline-flex;align-items:center;gap:8px;padding:9px 16px;border-radius:10px;border:1px solid var(--border);background:var(--bg-card);color:var(--text);font-weight:600;font-size:.88rem}.complete-btn.done{background:#22c55e26;border-color:var(--success);color:var(--success)}.section-block{margin-bottom:28px}.section-title{font-size:1.2rem;font-weight:700;margin-bottom:14px;display:flex;align-items:center;gap:8px}.concepts-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:14px}.concept-card{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);padding:16px}.concept-card h4{font-size:.98rem;color:var(--accent);margin-bottom:6px}.concept-card p{font-size:.86rem;color:var(--text-muted);margin-bottom:10px}.mental-model{background:#fbbf2414;border-left:3px solid var(--warning);padding:9px 12px;border-radius:6px;font-size:.82rem;color:#fde68a}.prereq-list{display:flex;flex-wrap:wrap;gap:6px;margin-top:10px}.prereq-chip{font-size:.72rem;padding:2px 8px;border-radius:999px;background:var(--bg-elevated);border:1px solid var(--border);color:var(--text-muted)}.content-card{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);padding:20px;margin-bottom:14px}.content-card h3{font-size:1.05rem;margin-bottom:8px}.content-card p{font-size:.92rem;color:#cbd5e1;white-space:pre-line}.code-box{margin-top:14px;background:#090d16;border:1px solid var(--border);border-radius:10px;overflow:hidden}.code-header{display:flex;justify-content:space-between;align-items:center;padding:6px 12px;background:#ffffff08;border-bottom:1px solid var(--border);font-size:.74rem;color:var(--text-dim);font-family:var(--font-mono)}.code-box pre{padding:14px;overflow-x:auto;font-family:var(--font-mono);font-size:.83rem;line-height:1.55;color:#e2e8f0}.quiz-card{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);padding:18px;margin-bottom:14px}.quiz-options{display:flex;flex-direction:column;gap:8px;margin-top:12px}.quiz-opt{text-align:left;padding:10px 14px;border-radius:8px;border:1px solid var(--border);background:var(--bg-elevated);color:var(--text);font-size:.88rem;transition:border-color .15s,background .15s}.quiz-opt:hover:not(:disabled){border-color:var(--accent)}.quiz-opt.correct{border-color:var(--success);background:#22c55e26}.quiz-opt.wrong{border-color:var(--danger);background:#ef444426}.quiz-exp{margin-top:10px;padding:10px 12px;border-radius:8px;background:#38bdf817;font-size:.84rem;color:#bae6fd}.practice-actions{display:flex;gap:10px;margin-top:12px;flex-wrap:wrap}.btn-sm{padding:6px 12px;border-radius:8px;border:1px solid var(--border);background:var(--bg-elevated);color:var(--text);font-size:.8rem;font-weight:600}.reveal-box{margin-top:10px;padding:12px 14px;border-radius:8px;background:#0b1220;border:1px solid var(--border);font-size:.86rem;white-space:pre-line;color:#cbd5e1}.graph-wrap{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);padding:18px;overflow-x:auto}.mobile-toggle{display:none;padding:8px 12px;border-radius:8px;border:1px solid var(--border);background:var(--bg-elevated);color:var(--text);font-size:.85rem}@media(max-width:900px){.sidebar{position:fixed;left:-310px;z-index:40;transition:left .25s ease}.sidebar.open{left:0}.mobile-toggle{display:inline-flex;align-items:center;gap:6px}.main{padding:20px 16px 48px}}