:root{
  --sb: 288px; --maxw: 820px;
  --bg:#ffffff; --fg:#1b1f24; --muted:#5c6672; --link:#0b6bcb; --link-hover:#094f97;
  --border:#e3e7ec; --sidebar-bg:#f7f8fa; --code-bg:#f0f2f5; --code-fg:#b4245a;
  --pre-bg:#1f2530; --pre-fg:#e7ebf0; --active-bg:#e9f1fb; --accent:#0b6bcb; --sel:#cfe3fb;
}
@media (prefers-color-scheme: dark){
  :root{
    --bg:#12161c; --fg:#e6e9ee; --muted:#9aa4b1; --link:#6db3ff; --link-hover:#96caff;
    --border:#2a313c; --sidebar-bg:#161b22; --code-bg:#212936; --code-fg:#ff9bbd;
    --pre-bg:#0c0f14; --pre-fg:#e7ebf0; --active-bg:#1b2735; --accent:#6db3ff; --sel:#2c435f;
  }
}
*{ box-sizing:border-box; }
html{ scroll-behavior:smooth; }
body{ margin:0; background:var(--bg); color:var(--fg);
  font-family:system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif; font-size:16px; line-height:1.65; }
::selection{ background:var(--sel); }
a{ color:var(--link); text-decoration:none; }
a:hover{ color:var(--link-hover); text-decoration:underline; }

.sidebar{ position:fixed; top:0; left:0; width:var(--sb); height:100vh; overflow-y:auto;
  background:var(--sidebar-bg); border-right:1px solid var(--border); padding:18px 14px 40px; }
.brand a{ font-weight:700; font-size:1.05rem; color:var(--fg); }
.brand .ver{ color:var(--muted); font-size:.8rem; margin-top:2px; }
.search{ position:relative; margin:14px 0 10px; }
.search input{ width:100%; padding:8px 10px; font-size:.92rem; color:var(--fg);
  background:var(--bg); border:1px solid var(--border); border-radius:7px; }
.search input:focus{ outline:2px solid var(--accent); border-color:var(--accent); }
.results{ position:absolute; z-index:20; left:0; right:0; top:calc(100% + 4px); max-height:62vh; overflow-y:auto;
  background:var(--bg); border:1px solid var(--border); border-radius:8px; box-shadow:0 6px 24px rgba(0,0,0,.14); }
.results a{ display:block; padding:8px 11px; border-bottom:1px solid var(--border); color:var(--fg); }
.results a:last-child{ border-bottom:0; }
.results a:hover{ background:var(--active-bg); text-decoration:none; }
.results .rt{ display:block; font-weight:600; font-size:.9rem; }
.results .rx{ display:block; color:var(--muted); font-size:.8rem; margin-top:2px; }
.results .nores{ padding:10px 11px; color:var(--muted); font-size:.88rem; }

.nav{ list-style:none; margin:8px 0 0; padding:0; }
.nav > li > a{ display:block; padding:5px 9px; border-radius:6px; color:var(--fg); font-size:.94rem; }
.nav > li > a:hover{ background:var(--active-bg); text-decoration:none; }
.nav > li.active > a{ background:var(--active-bg); color:var(--accent); font-weight:600; box-shadow:inset 3px 0 0 var(--accent); }
.sub{ list-style:none; margin:2px 0 6px; padding:0 0 0 12px; }
.sub a{ display:block; padding:3px 9px; font-size:.86rem; color:var(--muted); border-left:2px solid var(--border); }
.sub a:hover{ color:var(--fg); text-decoration:none; }
.sub a.here{ color:var(--accent); border-left-color:var(--accent); font-weight:600; }

main{ margin-left:var(--sb); padding:32px 40px 80px; }
article{ max-width:var(--maxw); margin:0 auto; }
article h1{ font-size:1.9rem; line-height:1.2; margin:.2em 0 .7em; }
article h2{ font-size:1.35rem; margin:1.8em 0 .5em; padding-bottom:.2em; border-bottom:1px solid var(--border); }
article h3{ font-size:1.1rem; margin:1.4em 0 .4em; }
article p, article ul, article ol{ margin:.6em 0; }
article li{ margin:.25em 0; }
article strong{ font-weight:600; }

code{ font-family:"Cascadia Code",Consolas,ui-monospace,monospace; font-size:.9em;
  background:var(--code-bg); color:var(--code-fg); padding:.12em .38em; border-radius:5px; }
pre{ background:var(--pre-bg); color:var(--pre-fg); padding:14px 16px; border-radius:9px; overflow-x:auto; line-height:1.5; }
pre code{ background:none; color:inherit; padding:0; font-size:.86rem; }
kbd{ font-size:.82em; background:var(--code-bg); border:1px solid var(--border); border-bottom-width:2px; border-radius:5px; padding:.05em .4em; }

blockquote{ margin:.9em 0; padding:.4em 1em; border-left:4px solid var(--accent); background:var(--active-bg); border-radius:0 8px 8px 0; }
blockquote p{ margin:.3em 0; }

table{ border-collapse:collapse; width:100%; margin:1em 0; font-size:.94rem; display:block; overflow-x:auto; }
th, td{ border:1px solid var(--border); padding:7px 11px; text-align:left; vertical-align:top; }
thead th{ background:var(--sidebar-bg); }
tbody tr:nth-child(even){ background:rgba(127,127,127,.06); }

figure{ margin:1.3em 0; text-align:center; }
figure img{ max-width:100%; height:auto; border:1px solid var(--border); border-radius:8px; }
figcaption{ color:var(--muted); font-size:.85rem; font-style:italic; margin-top:.5em; }
article img{ max-width:100%; height:auto; }

.home-sub{ color:var(--muted); font-size:1.05rem; margin-top:0; }
.chapter-list{ list-style:none; padding:0; margin:1.5em 0 0; }
.chapter-list > li{ padding:14px 0; border-top:1px solid var(--border); }
.chapter-list > li > a{ font-weight:600; font-size:1.08rem; }
.chapter-list p{ margin:.3em 0 0; color:var(--muted); font-size:.92rem; }

.pager{ display:flex; justify-content:space-between; gap:16px; margin-top:48px; padding-top:20px; border-top:1px solid var(--border); }
.pager a{ display:block; max-width:48%; padding:10px 14px; border:1px solid var(--border); border-radius:9px; color:var(--fg); font-weight:600; }
.pager a:hover{ border-color:var(--accent); text-decoration:none; }
.pager a span{ display:block; color:var(--muted); font-size:.75rem; font-weight:500; text-transform:uppercase; letter-spacing:.04em; }
.pager a.next{ margin-left:auto; text-align:right; }

.menu-toggle{ display:none; position:fixed; top:12px; left:12px; z-index:40; width:42px; height:42px;
  font-size:1.3rem; background:var(--bg); color:var(--fg); border:1px solid var(--border); border-radius:9px; cursor:pointer; }
.scrim{ display:none; position:fixed; inset:0; background:rgba(0,0,0,.4); z-index:25; }
.skip{ position:absolute; left:-9999px; }
.skip:focus{ left:8px; top:8px; z-index:50; background:var(--bg); padding:6px 10px; border:1px solid var(--border); border-radius:6px; }

@media (max-width: 920px){
  .menu-toggle{ display:block; }
  .sidebar{ transform:translateX(-100%); transition:transform .15s ease; z-index:30; width:min(88vw,320px); }
  body.nav-open .sidebar{ transform:none; }
  body.nav-open .scrim{ display:block; }
  main{ margin-left:0; padding:64px 20px 60px; }
}