:root{--ground:#F5F6F8;--panel:#FFFFFF;--ink:#14181E;--ink-soft:#586273;--ink-faint:#8A93A2;--line:#E4E7EC;--line-strong:#D3D8E0;--accent:#FF7A00;--accent-deep:#FF5E00;--accent-soft:#FFF2E6;--accent-line:#FFD7B0;--sidebar:#0E1117;--sidebar-2:#161B22;--sidebar-ink:#C7CDD7;--sidebar-faint:#7B8696;--grad:linear-gradient(90deg,#FFB020,#FF7A00,#FF5E00);--sans:"Segoe UI",system-ui,-apple-system,"Helvetica Neue",Arial,sans-serif;--mono:"Cascadia Code","Consolas",ui-monospace,"SF Mono",Menlo,monospace}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--ground);color:var(--ink);font-family:var(--sans);font-size:17px;line-height:1.65;-webkit-font-smoothing:antialiased}.sidebar{position:fixed;top:0;left:0;width:284px;height:100vh;overflow-y:auto;background:var(--sidebar);color:var(--sidebar-ink);border-right:1px solid #000;padding:22px 16px 40px;scrollbar-width:thin;scrollbar-color:var(--accent) var(--sidebar-2)}.sidebar::-webkit-scrollbar{width:10px}.sidebar::-webkit-scrollbar-track{background:var(--sidebar-2)}.sidebar::-webkit-scrollbar-thumb{background:linear-gradient(180deg,var(--accent-amber),var(--accent-deep));border-radius:8px;border:2px solid var(--sidebar)}.brandlink{display:block;text-decoration:none;color:#e7eaf0;font-size:1.05rem;margin:4px 8px 22px;font-weight:600}.brandlink b{background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}.navsec{margin-bottom:18px}.navtitle{display:block;font-family:var(--mono);font-size:.68rem;letter-spacing:.14em;text-transform:uppercase;color:var(--sidebar-faint);margin:0 0 6px;padding:4px 8px;border-radius:7px;text-decoration:none}.navtitle:hover{color:#fff;background:var(--sidebar-2)}.navtitle.active{color:var(--accent)}.navitem{display:flex;align-items:center;gap:8px;text-decoration:none;color:var(--sidebar-ink);font-size:.9rem;padding:7px 10px;border-radius:8px;margin:1px 0}.navitem:hover{background:var(--sidebar-2);color:#fff}.navitem.active{background:var(--accent-soft);color:var(--accent-deep);font-weight:600}.navitem .mark{flex:0 0 auto;width:1.05em;text-align:center;font-size:.78rem;color:var(--sidebar-faint)}.navitem .navlabel{flex:1}.navitem.is-done{color:#a7e9c4}.navitem.is-done .mark{color:#3dd68c}.navitem.is-locked{color:var(--sidebar-faint);opacity:.55;cursor:not-allowed}.navitem.is-locked:hover{background:transparent;color:var(--sidebar-faint)}.content{margin-left:284px;margin-right:248px;padding:48px clamp(24px,4vw,64px)}.menu-btn{display:none}.prose h1{font-size:clamp(1.8rem,4vw,2.6rem);font-weight:800;letter-spacing:-.02em;line-height:1.12;margin:0 0 8px}.prose h2{font-size:clamp(1.3rem,2.6vw,1.7rem);font-weight:700;margin:38px 0 10px;padding-bottom:6px;border-bottom:1px solid var(--line)}.prose h3{font-size:1.15rem;font-weight:700;margin:26px 0 6px}.prose h4{font-size:1rem;font-weight:700;margin:20px 0 4px}.prose p,.prose li{font-size:1.02rem}.prose a{color:var(--accent-deep);text-decoration:none;border-bottom:1px solid var(--accent-line)}.prose a:hover{border-bottom-color:var(--accent-deep)}.prose ul,.prose ol{padding-left:22px}.prose li{margin:6px 0}.prose blockquote{margin:18px 0;padding:12px 18px;background:var(--accent-soft);border-left:3px solid var(--accent);border-radius:0 10px 10px 0;color:#7a4a1c}.prose blockquote p{margin:4px 0}.prose :not(pre)>code{font-family:var(--mono);font-size:.9em;background:#eef0f3;padding:2px 6px;border-radius:5px}.prose pre{padding:18px 20px;border-radius:12px;overflow-x:auto;margin:18px 0;border:1px solid var(--line-strong)}.prose pre code{background:none;padding:0;font-size:.86rem;line-height:1.6}.prose table{border-collapse:collapse;width:100%;margin:18px 0;font-size:.95rem;display:block;overflow-x:auto}.prose th,.prose td{border:1px solid var(--line);padding:9px 13px;text-align:left}.prose th{background:var(--panel);font-weight:700}.prose hr{border:none;border-top:1px solid var(--line);margin:32px 0}.prose img{max-width:100%}.hero-home .eyebrow{font-family:var(--mono);font-size:.72rem;letter-spacing:.16em;text-transform:uppercase;color:var(--accent)}.hero-home h1{font-size:clamp(2rem,5vw,3.2rem);font-weight:800;letter-spacing:-.025em;line-height:1.06;margin:14px 0 0}.hero-home h1 .g{background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}.hero-home p{color:var(--ink-soft);font-size:1.1rem;max-width:62ch;margin:16px 0 0}.cards{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin-top:34px}.hcard{display:block;text-decoration:none;color:inherit;background:var(--panel);border:1px solid var(--line);border-top:3px solid var(--accent);border-radius:14px;padding:22px}.hcard:hover{border-color:var(--accent-line);box-shadow:0 6px 20px #14181f0f}.hcard .n{font-family:var(--mono);font-size:.68rem;letter-spacing:.1em;text-transform:uppercase;color:var(--accent-deep);font-weight:700}.hcard h3{margin:8px 0 4px;font-size:1.15rem}.hcard p{margin:0;color:var(--ink-soft);font-size:.95rem}.foot{margin-top:48px;padding-top:20px;border-top:1px solid var(--line);color:var(--ink-faint);font-size:.85rem}.foot a{text-decoration:none;font-weight:700;background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}@media(max-width:900px){.sidebar{transform:translate(-100%);transition:transform .25s ease;z-index:60;width:82%;max-width:320px}body.nav-open .sidebar{transform:translate(0)}.content{margin-left:0;padding:66px 7vw}.menu-btn{display:flex;align-items:center;justify-content:center;position:fixed;top:14px;left:14px;z-index:70;width:44px;height:44px;border-radius:10px;border:1px solid var(--line-strong);background:var(--panel);font-size:1.2rem;cursor:pointer}.cards{grid-template-columns:1fr}}@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important}.sidebar,#prog-fill{transition:none}}html{scrollbar-width:thin;scrollbar-color:var(--accent) var(--ground)}body::-webkit-scrollbar{width:12px}body::-webkit-scrollbar-track{background:var(--ground)}body::-webkit-scrollbar-thumb{background:linear-gradient(180deg,var(--accent-amber),var(--accent-deep));border-radius:8px}.progress{display:flex;align-items:center;gap:8px;margin:0 8px 18px}.pbar{flex:1;height:7px;background:var(--sidebar-2);border-radius:6px;overflow:hidden}#prog-fill{height:100%;width:0;background:linear-gradient(90deg,var(--accent-amber),var(--accent-deep));transition:width .45s ease}.ptext{font-family:var(--mono);font-size:.64rem;color:var(--sidebar-faint);white-space:nowrap}.lessonfoot{margin-top:38px;padding-top:22px;border-top:1px solid var(--line);display:flex;align-items:center;gap:16px;flex-wrap:wrap}#mark-done{font:inherit;font-weight:700;font-size:.95rem;padding:11px 20px;border-radius:10px;border:1px solid var(--accent);background:var(--accent);color:#fff;cursor:pointer;min-height:44px}#mark-done:hover{background:var(--accent-deep);border-color:var(--accent-deep)}#mark-done.done{background:#e4f6ec;color:#1e9e5a;border-color:#b6e6c8}#mark-done:disabled{opacity:.5;cursor:not-allowed}.next-lesson{text-decoration:none;font-weight:700;color:var(--accent-deep);min-height:44px;display:inline-flex;align-items:center}.locknotice{display:flex;gap:14px;align-items:flex-start;background:#fdf6ec;border:1px solid var(--accent-line);border-radius:14px;padding:22px 24px;margin:8px 0}.locknotice .lk{font-size:1.7rem;line-height:1}.locknotice strong{font-size:1.1rem}.locknotice p{margin:6px 0;color:var(--ink-soft)}.locknotice .lock-prev{font-weight:700;color:var(--accent-deep);text-decoration:none}.lc{position:relative}.lc .mark{position:absolute;top:14px;right:16px;font-size:.9rem}.lc.is-locked{opacity:.55;cursor:not-allowed}.lc.is-done .mark{color:#3dd68c}.prose{max-width:840px}.rail{position:fixed;top:0;right:0;width:248px;height:100vh;overflow-y:auto;padding:28px 18px;border-left:1px solid var(--line);background:var(--panel)}.rail-box{background:var(--ground);border:1px solid var(--line);border-radius:13px;padding:16px;margin-bottom:14px}.rail-label{font-family:var(--mono);font-size:.64rem;letter-spacing:.12em;text-transform:uppercase;color:var(--ink-faint);margin:0 0 8px}.rail-pbar{height:7px;background:var(--line);border-radius:6px;overflow:hidden}#rail-fill{height:100%;width:0;background:linear-gradient(90deg,var(--accent-amber),var(--accent-deep));transition:width .45s ease}.rail-prog{font-family:var(--mono);font-size:.7rem;color:var(--ink-soft);margin:8px 0 12px}.rail-continue{display:inline-flex;min-height:40px;align-items:center;font-weight:700;font-size:.86rem;color:#fff;background:var(--accent);text-decoration:none;padding:8px 14px;border-radius:9px}.rail-continue:hover{background:var(--accent-deep)}.rail-current{font-weight:700;font-size:.95rem;margin:0 0 10px}.rail-next-link{display:block;text-decoration:none;color:var(--accent-deep);font-weight:600;font-size:.86rem}.rail-next-link.locked{color:var(--ink-faint);font-weight:400}@media(max-width:1200px){.rail{display:none}.content{margin-right:0}}.navitem.startlink{background:var(--accent);color:#fff;border:1px solid var(--accent);margin:2px 0 14px;font-weight:700}.navitem.startlink .mark{color:#fff}.navitem.startlink:hover{background:var(--accent-deep);border-color:var(--accent-deep);color:#fff}.home-cta{display:inline-flex;align-items:center;min-height:48px;margin-top:22px;text-decoration:none;font-weight:700;background:var(--accent);color:#fff;padding:13px 22px;border-radius:12px}.home-cta:hover{background:var(--accent-deep)}.navitem.playlink{background:var(--sidebar-2);border:1px solid #2A323C;margin:2px 0 16px;color:#fff;font-weight:600}.navitem.playlink .mark{color:var(--accent-amber)}.navitem.playlink:hover{border-color:var(--accent);background:var(--sidebar-2);color:#fff}.sidebar,.rail{transition:transform .25s ease}.side-collapse,.rail-collapse{position:absolute;top:16px;right:14px;width:30px;height:30px;border-radius:8px;cursor:pointer;font-size:1rem;line-height:1;display:flex;align-items:center;justify-content:center}.side-collapse{background:#232a33;border:1px solid #2A323C;color:#c7cdd7}.side-collapse:hover{color:#fff}.rail-collapse{background:var(--ground);border:1px solid var(--line);color:var(--ink-soft)}.rail-collapse:hover{color:var(--ink)}.side-open,.rail-open{display:none;position:fixed;top:14px;z-index:65;width:40px;height:40px;border-radius:10px;border:1px solid var(--line-strong);background:var(--panel);color:var(--ink);cursor:pointer;font-size:1.1rem;align-items:center;justify-content:center;box-shadow:0 2px 10px #00000014}.side-open{left:12px}.rail-open{right:12px}@media(min-width:901px){body.nav-collapsed .sidebar{transform:translate(-100%)}body.nav-collapsed .content{margin-left:0}body.nav-collapsed .side-open{display:flex}}@media(min-width:1201px){body.rail-collapsed .rail{transform:translate(100%)}body.rail-collapsed .content{margin-right:0}body.rail-collapsed .rail-open{display:flex}}@media(max-width:900px){.side-collapse{display:none}}@media(max-width:1200px){.rail-collapse{display:none}}.quiz{border:1px solid var(--line);border-radius:14px;margin:28px 0;background:var(--panel);overflow:hidden;max-width:840px}.quiz-head{background:#0e1117;color:#e7eaf0;padding:12px 16px;font-weight:700;font-size:.95rem}.quiz-body{padding:18px 18px 20px}.quiz-q{padding:14px 0;border-top:1px solid var(--line)}.quiz-q:first-child{border-top:none}.quiz-qt{margin:0 0 10px;font-weight:600;display:flex;gap:10px;align-items:baseline}.quiz-n{font-family:var(--mono);font-size:.78rem;background:var(--accent-soft);color:var(--accent-deep);border:1px solid var(--accent-line);width:24px;height:24px;border-radius:7px;display:inline-flex;align-items:center;justify-content:center;flex:0 0 auto}.quiz-opts{display:flex;flex-direction:column;gap:8px}.quiz-opt{font:inherit;text-align:left;padding:11px 14px;border:1px solid var(--line-strong);background:var(--ground);border-radius:10px;cursor:pointer;min-height:44px}.quiz-opt:hover:not(:disabled){border-color:var(--accent)}.quiz-opt:disabled{cursor:default}.quiz-opt.correct{background:#e4f6ec;border-color:#9bdcb4;color:#1e7a45;font-weight:700}.quiz-opt.wrong{background:#fde8e8;border-color:#f0bcb6;color:#c0392b}.quiz-explain{margin:10px 0 0;font-size:.9rem;color:var(--ink-soft);background:var(--accent-soft);border-radius:8px;padding:9px 12px}.quiz-result{margin:16px 0 0;font-weight:700;font-size:1.02rem}.pg{border:1px solid var(--line);border-radius:14px;overflow:hidden;margin:28px 0;background:var(--panel);max-width:none}.pg-head{background:#0e1117;color:#e7eaf0;padding:12px 16px;font-weight:700;font-size:.95rem;display:flex;align-items:center;gap:10px;flex-wrap:wrap}.pg-emoji{font-size:1.1rem}.pg-hint{font-family:var(--mono);font-size:.7rem;color:#8b93a0;font-weight:400}.pg-grid{display:grid;grid-template-columns:1fr 1fr}.pg-left{display:flex;flex-direction:column;border-right:1px solid var(--line);background:#0a0d12}.pg-tabs{display:flex;gap:4px;padding:8px 8px 0}.pg-tab{font-family:var(--mono);font-size:.78rem;padding:7px 13px;border:none;background:transparent;color:#8b93a0;cursor:pointer;border-radius:8px 8px 0 0;min-height:36px}.pg-tab.is-on{background:#0e1117;color:var(--accent-amber)}.pg-code{flex:1;min-height:240px;border:none;background:#0e1117;color:#e7eaf0;font-family:var(--mono);font-size:.85rem;line-height:1.55;padding:14px 16px;resize:vertical;outline:none;width:100%}.pg-actions{display:flex;gap:8px;padding:10px;flex-wrap:wrap}.pg-actions button{font-size:.8rem;font-weight:700;padding:8px 13px;border-radius:8px;border:1px solid #2A323C;background:#161b22;color:#e7eaf0;cursor:pointer;min-height:40px}.pg-actions button:hover{border-color:var(--accent)}.pg-run{background:var(--accent)!important;border-color:var(--accent)!important;color:#fff!important}.pg-run:hover{background:var(--accent-deep)!important}.pg-preview{border:none;width:100%;min-height:300px;background:#fff}@media(max-width:760px){.pg-grid{grid-template-columns:1fr}.pg-left{border-right:none;border-bottom:1px solid var(--line)}}