.crumb{font-size:.8rem;color:var(--sl,#94a3b8);margin-bottom:1rem}
.crumb a{color:var(--sl,#94a3b8)}
.crumb a:hover{color:var(--blue,#38bdf8)}
h1{font-size:1.7rem;margin-bottom:.5rem;color:var(--heading,#f8fafc)}
.lesson-tag{display:inline-block;font-size:.72rem;font-weight:800;color:var(--blue,#38bdf8);background:rgba(56,189,248,.12);padding:.3rem .8rem;border-radius:20px;text-transform:uppercase;margin-bottom:1rem}
.lede{font-size:1.05rem;color:var(--text,#e2e8f0);line-height:1.75;margin-bottom:1.5rem}
.lede .hl{color:var(--heading,#f8fafc);font-weight:600}
.section{margin:2.4rem 0}
.section-head{display:flex;align-items:center;gap:.7rem;margin-bottom:1rem}
.section-num{background:linear-gradient(135deg,#38bdf8,#a78bfa);color:#020617;width:30px;height:30px;border-radius:9px;display:flex;align-items:center;justify-content:center;font-weight:800;font-size:.95rem;flex-shrink:0}
.section-head h2{font-size:1.25rem;color:var(--heading,#f8fafc);margin:0}
.section p{color:var(--sl,#94a3b8);font-size:.96rem;margin-bottom:1rem}
.section p strong,.section li strong{color:var(--heading,#f8fafc)}
.section ul,.section ol{margin:0 0 1rem 1.2rem;color:var(--sl,#94a3b8);font-size:.95rem}
.section li{margin-bottom:.5rem}
.def-box{background:linear-gradient(120deg,rgba(56,189,248,.12),rgba(45,212,191,.1));border:1px solid rgba(56,189,248,.3);border-radius:12px;padding:1.3rem 1.4rem;margin:1.5rem 0}
.def-label{font-size:.72rem;font-weight:800;color:var(--blue,#38bdf8);text-transform:uppercase;letter-spacing:.05em;margin-bottom:.5rem}
.def-box p{margin:0;color:var(--heading,#f8fafc);font-size:1.02rem;font-weight:500;line-height:1.6}
.map-table{width:100%;border-collapse:collapse;font-size:.88rem;margin:1rem 0}
.map-table th,.map-table td{border:1px solid var(--bdr,rgba(148,163,184,.1));padding:.65rem .75rem;text-align:left;vertical-align:top}
.map-table th{background:var(--bg3,#0c1526);color:var(--heading,#f8fafc);font-weight:700}
.map-table td{color:var(--sl,#94a3b8)}
.map-table code{font-family:'JetBrains Mono',monospace;font-size:.8rem;color:var(--teal,#2dd4bf)}
.trap-box,.infobox,.angle-box,.analogy{border-radius:10px;padding:1.1rem 1.3rem;margin:1.4rem 0}
.trap-box{background:rgba(248,113,113,.07);border:1px solid rgba(248,113,113,.25);border-left:3px solid #f87171}
.trap-label{font-size:.72rem;font-weight:800;color:#f87171;text-transform:uppercase;letter-spacing:.05em;margin-bottom:.5rem}
.trap-box p,.infobox p,.angle-box p,.analogy p{margin:0;color:var(--text,#e2e8f0);font-size:.92rem}
.infobox{background:rgba(56,189,248,.06);border:1px solid rgba(56,189,248,.2)}
.angle-box{background:rgba(167,139,250,.08);border:1px solid rgba(167,139,250,.28);border-left:3px solid #a78bfa}
.angle-label{font-size:.72rem;font-weight:800;color:#a78bfa;text-transform:uppercase;letter-spacing:.05em;margin-bottom:.5rem}
.analogy{background:linear-gradient(120deg,rgba(251,191,36,.08),rgba(167,139,250,.06));border:1px solid rgba(251,191,36,.22);border-left:3px solid #fbbf24}
.analogy-label{font-size:.72rem;font-weight:800;color:#fbbf24;text-transform:uppercase;letter-spacing:.05em;margin-bottom:.5rem}
.reason-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(210px,1fr));gap:.9rem;margin:1.3rem 0}
.reason-card{background:var(--bg3,#0c1526);border:1px solid var(--bdr,rgba(148,163,184,.1));border-radius:10px;padding:1.1rem}
.reason-card h4{color:var(--heading,#f8fafc);font-size:.92rem;margin:.35rem 0}
.reason-card p{color:var(--sl,#94a3b8);font-size:.82rem;margin:0;line-height:1.55}
.diagram-wrap{background:var(--bg3,#0c1526);border:1px solid var(--bdr,rgba(148,163,184,.1));border-radius:12px;padding:1.2rem 1rem;margin:1.4rem 0;overflow-x:auto}
.diagram-wrap svg{display:block;margin:0 auto;max-width:100%;height:auto}
.diagram-caption{text-align:center;color:var(--sl,#94a3b8);font-size:.78rem;margin-top:.75rem;line-height:1.45}
.wavedrom-box{background:#fff;border:1px solid var(--bdr,rgba(148,163,184,.1));border-radius:12px;padding:1rem;margin:1.2rem 0;overflow-x:auto}
.key-takeaway{background:linear-gradient(120deg,rgba(56,189,248,.1),rgba(45,212,191,.1));border:1px solid rgba(56,189,248,.25);border-radius:12px;padding:1.3rem 1.4rem;margin:2rem 0}
.key-takeaway h3{color:var(--blue,#38bdf8);font-size:.95rem;margin-bottom:.6rem}
.key-takeaway ul{margin-left:1.1rem;color:var(--text,#e2e8f0);font-size:.9rem}
.key-takeaway li{margin-bottom:.4rem}
.lesson-nav{display:flex;justify-content:space-between;gap:1rem;flex-wrap:wrap;margin-top:2rem;padding-top:1.5rem;border-top:1px solid var(--bdr,rgba(148,163,184,.1))}
.lesson-nav a{font-weight:600}
.lab-panel{background:var(--bg2,#080d1a);border:1px solid var(--bdr,rgba(148,163,184,.1));border-radius:14px;padding:1.2rem;margin:1.4rem 0}
.lab-controls{display:flex;flex-wrap:wrap;gap:.6rem;align-items:center;margin:.8rem 0}
.lab-controls button{font-family:Outfit,sans-serif;font-weight:700;border:none;border-radius:8px;padding:.55rem 1rem;cursor:pointer;background:var(--blue,#38bdf8);color:#020617}
.lab-controls button.ghost{background:var(--bg3,#0c1526);color:var(--text,#e2e8f0);border:1px solid var(--bdr,rgba(148,163,184,.1))}
.lab-stat{font-size:.82rem;color:var(--sl,#94a3b8);font-family:'JetBrains Mono',monospace}
.container{max-width:760px;margin:0 auto;padding:2rem 1rem}
.no-access{text-align:center;padding:5rem 1.5rem}
.no-access h1{color:#f87171}
#authLoading{position:fixed;inset:0;background:var(--bg,#020617);z-index:9999;display:flex;align-items:center;justify-content:center}
.auth-spinner{width:36px;height:36px;border:3px solid rgba(56,189,248,.15);border-top-color:var(--blue,#38bdf8);border-radius:50%;animation:afspin .7s linear infinite}
@keyframes afspin{to{transform:rotate(360deg)}}
.navbar{background:var(--nav-bg,rgba(2,6,23,.97));border-bottom:1px solid var(--bdr,rgba(148,163,184,.1));padding:1rem;display:flex;justify-content:space-between;align-items:center;position:sticky;top:0;z-index:50;gap:.65rem;flex-wrap:wrap}
.navbar-logo{font-size:1.15rem;font-weight:700;color:var(--nav-text,#fff)}
.navbar-right{display:flex;align-items:center;gap:.65rem}
.back-link{color:var(--sl,#94a3b8);font-size:.9rem;text-decoration:none}
.back-link:hover{color:var(--blue,#38bdf8)}
footer{border-top:1px solid var(--bdr,rgba(148,163,184,.1));padding:2rem;text-align:center;font-size:.8rem;color:var(--sl,#94a3b8);background:var(--bg2,#080d1a);margin-top:3rem}
.af-toc{background:var(--bg3,#0c1526);border:1px solid var(--bdr,rgba(148,163,184,.1));border-radius:12px;padding:1.1rem 1.25rem;margin:0 0 1.8rem}
.af-toc-label{font-size:.72rem;font-weight:800;color:var(--blue,#38bdf8);text-transform:uppercase;letter-spacing:.05em;margin-bottom:.55rem}
.af-toc ol{margin:0 0 0 1.15rem;color:var(--sl,#94a3b8);font-size:.9rem}
.af-toc li{margin:.28rem 0}
.af-toc a{color:var(--text,#e2e8f0)}
.af-faq-sec details{background:var(--bg3,#0c1526);border:1px solid var(--bdr,rgba(148,163,184,.1));border-radius:10px;padding:.85rem 1.05rem;margin:.65rem 0}
.af-faq-sec summary{cursor:pointer;font-weight:650;color:var(--heading,#f8fafc);font-size:.95rem}
.af-faq-sec details p{margin:.65rem 0 0;color:var(--sl,#94a3b8);font-size:.92rem}
.af-signin-banner{display:none;background:rgba(251,191,36,.1);border:1px solid rgba(251,191,36,.35);color:#fde68a;border-radius:10px;padding:.85rem 1.1rem;margin:0 auto 1.25rem;max-width:760px;font-size:.9rem}
.af-signin-banner a{color:#38bdf8;font-weight:700}
#back-to-top{position:fixed;bottom:1.5rem;right:1.25rem;z-index:200;background:#38bdf8;color:#020617;border:none;border-radius:50%;width:44px;height:44px;font-size:1.15rem;font-weight:800;cursor:pointer;display:none;align-items:center;justify-content:center;box-shadow:0 4px 16px rgba(56,189,248,.35)}
#back-to-top.show{display:flex}
@media(max-width:768px){.container{padding:1.25rem .9rem}h1{font-size:1.35rem}}