:root { --bg: #f6f7f9; --surface: #fff; --text: #1a1d23; --muted: #5f6672; --border: #e3e5ea; --primary: #2563eb; --todo: #fff3cd; color-scheme: light; }
@media (prefers-color-scheme: dark) {
  :root { --bg: #0f1115; --surface: #181b21; --text: #eceef2; --muted: #9aa1ad; --border: #2b303a; --primary: #7aa2ff; --todo: #4a3b10; color-scheme: dark; }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--text); font: 15px/1.65 system-ui, -apple-system, "Segoe UI", Roboto, "Noto Sans", "Noto Sans Devanagari", sans-serif; }
header { position: sticky; top: 0; background: var(--surface); border-bottom: 1px solid var(--border); padding: .7rem 1rem; padding-top: calc(.7rem + env(safe-area-inset-top)); display: flex; gap: .75rem; align-items: center; z-index: 2; }
header a { color: var(--primary); text-decoration: none; font-weight: 600; }
header b { flex: 1; }
main { max-width: 760px; margin: 0 auto; padding: 1rem 1rem 3rem; }
h1 { font-size: 1.6rem; margin: .5rem 0 .25rem; line-height: 1.25; }
h2 { font-size: 1.15rem; margin: 1.8rem 0 .5rem; padding-top: .5rem; border-top: 1px solid var(--border); }
h3 { font-size: 1rem; margin: 1.1rem 0 .3rem; }
p, li { margin: .35rem 0; }
ul, ol { padding-left: 1.3rem; }
a { color: var(--primary); }
.meta { color: var(--muted); font-size: .9rem; }
.box { background: var(--surface); border: 1px solid var(--border); border-radius: 12px; padding: .9rem 1rem; margin: 1rem 0; }
.box.hi { border-left: 4px solid var(--primary); }
table { width: 100%; border-collapse: collapse; font-size: .9rem; margin: .5rem 0; display: block; overflow-x: auto; }
th, td { border: 1px solid var(--border); padding: .45rem .55rem; text-align: left; vertical-align: top; }
th { background: var(--surface); }
.todo { background: var(--todo); padding: 0 .25rem; border-radius: 4px; }
nav.toc { columns: 2; column-gap: 1.5rem; font-size: .9rem; }
@media (max-width: 560px) { nav.toc { columns: 1; } }