:root{--bg:#0b0f14;--surface:#121821;--text:#e8edf2;--muted:#a9b4c0;--accent:#00ddff;--border:#263140;--code:#0f141b;--max:46rem}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--text);font:17px/1.65 system-ui,-apple-system,"Segoe UI",Roboto,sans-serif}
a{color:var(--accent);word-break:break-word}
.skip{position:absolute;left:-9999px}.skip:focus{left:1rem;top:1rem;background:#fff;color:#000;padding:.5rem}
.top{position:sticky;top:0;z-index:10;display:flex;justify-content:space-between;align-items:center;gap:1rem;padding:.6rem 1rem;background:rgba(18,24,33,.96);border-bottom:1px solid var(--border)}
.brand{color:#fff;font-weight:700;text-decoration:none}.brand span{color:var(--muted);font-weight:500}
.tocmenu summary{cursor:pointer;color:var(--muted);list-style:none;padding:.3rem .7rem;border:1px solid var(--border);border-radius:6px}
.tocmenu[open] ol{position:absolute;right:.5rem;top:3rem;max-height:75vh;overflow:auto;width:min(22rem,94vw);background:var(--surface);border:1px solid var(--border);border-radius:8px;padding:.6rem 1rem .6rem 2rem;margin:0}
.tocmenu li{margin:.25rem 0}.tocmenu li.cur a{color:#fff;font-weight:700}
main{max-width:var(--max);margin:0 auto;padding:1.2rem 1rem 2rem}
h1{font-size:1.75rem;line-height:1.25;margin:.4rem 0 .6rem}
h2{font-size:1.35rem;margin-top:2.2rem;border-top:1px solid var(--border);padding-top:1rem}
h3{font-size:1.15rem;margin-top:1.6rem}h4,h5,h6{font-size:1rem}
.kicker{color:var(--accent);text-transform:uppercase;letter-spacing:.06em;font-size:.75rem;margin:0}
.lede{color:var(--muted);font-size:1.05rem}
img{max-width:100%;height:auto;background:#fff;border-radius:4px}
figure{margin:1rem 0}figcaption{color:var(--muted);font-size:.85rem}
pre{background:var(--code);border:1px solid var(--border);border-radius:6px;padding:.8rem;overflow-x:auto;font-size:.85rem;line-height:1.45}
code{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:.9em}
p code,li code{background:var(--code);padding:.05rem .3rem;border-radius:4px}
.tw{overflow-x:auto;margin:1rem 0}table{border-collapse:collapse;font-size:.9rem;min-width:60%}
th,td{border:1px solid var(--border);padding:.35rem .55rem;vertical-align:top}th{background:var(--surface)}
blockquote{margin:1rem 0;padding:.4rem 1rem;border-left:3px solid var(--accent);color:var(--muted);background:var(--surface)}
math{font-size:1.1em;font-family:"STIX Two Math","Cambria Math","Latin Modern Math","Noto Sans Math","DejaVu Serif",serif}math mi{text-transform:none;font-style:italic}math mi[mathvariant=normal]{font-style:normal}
math[display=block]{overflow-x:auto;max-width:100%;padding:.3rem 0}
.video{display:block;margin:1rem 0;padding:.8rem 1rem;border:1px solid var(--border);border-left:4px solid #ff4d4d;border-radius:6px;background:var(--surface);font-size:.95rem}
.soon{color:var(--muted)}
.extras{margin-top:2.5rem;padding:1rem;border:1px solid var(--border);border-radius:8px;background:var(--surface)}
.extras h2{border:0;margin-top:.5rem;padding-top:0}
.pn{display:flex;justify-content:space-between;gap:1rem;margin-top:2rem;padding-top:1rem;border-top:1px solid var(--border)}
.pn a{display:block;padding:.7rem 1rem;border:1px solid var(--border);border-radius:8px;text-decoration:none;max-width:48%}
.pn .next{margin-left:auto;text-align:right}
.btn{display:inline-block;background:var(--accent);color:#001018;font-weight:700;text-decoration:none;padding:.65rem 1.1rem;border-radius:8px;margin:.2rem .3rem .2rem 0}
.btn.alt{background:transparent;color:var(--accent);border:1px solid var(--accent)}
.hero{display:grid;gap:1.2rem;align-items:start}.hero .cover{width:min(240px,60vw);height:auto;margin:0 auto;display:block;box-shadow:0 10px 30px rgba(0,0,0,.6)}
.by{color:var(--muted);margin:.2rem 0 .8rem}
.cards{list-style:none;padding:0;margin:0}.cards li{margin:.5rem 0}
.cards a{display:flex;gap:.8rem;padding:.75rem .9rem;border:1px solid var(--border);border-radius:8px;text-decoration:none;color:var(--text);background:var(--surface)}
.cards .n{flex:0 0 2.4rem;color:var(--accent);font-weight:700}.cards small{color:var(--muted)}
.locked{padding:1.2rem;border:1px dashed var(--accent);border-radius:8px;margin:1.5rem 0}
.back{margin-top:2rem;color:var(--muted)}
.foot{border-top:1px solid var(--border);padding:1.2rem 1rem 2rem;text-align:center;color:var(--muted);font-size:.9rem}
.foot .support a{font-weight:700}.small{font-size:.85rem;color:var(--muted)}
@media(min-width:760px){.hero{grid-template-columns:240px 1fr}h1{font-size:2.1rem}}
.badge{display:inline-block;font-size:.75rem;font-weight:700;text-transform:uppercase;letter-spacing:.05em;padding:.15rem .5rem;border-radius:4px;background:#3a2a10;color:#ffcf70;margin:.2rem 0}.badge.free{background:#0f3324;color:#6ee7b7}
.tag{font-style:normal;font-size:.7rem;padding:.05rem .4rem;border-radius:4px;background:#3a2a10;color:#ffcf70;white-space:nowrap}.tag.free{background:#0f3324;color:#6ee7b7}
.buybox{margin:1.5rem 0;padding:1rem;border:1px solid var(--accent);border-radius:8px;background:var(--surface)}
.btn.disabled{background:#3b4652;color:#9aa6b2;cursor:not-allowed}
.soon-banner{margin:0 0 .6rem;padding:.4rem .7rem;border-radius:6px;background:#3a2a10;color:#ffcf70}