/* 7.35.3 Training and Education: the site's one stylesheet.
   White ground, ink, one working blue. Color belongs to meaning:
   amber = open, green = settled, red = defect in the text, gray = superseded.
   Serif appears only inside verbatim rule text. Mono carries data and wayfinding. */

:root{
  --bg:#FFFFFF; --ink:#16181D; --ink2:#4A4F58; --faint:#8A8F98; --hair:#E4E6EA; --wash:#F5F6F8;
  --blue:#2447C7; --bluewash:#EEF1FB;
  --open:#9A6700; --openwash:#FBF3DF;
  --settled:#1E6B45; --settledwash:#EAF4EE;
  --defect:#B42318; --defectwash:#FBEDEB;
  --sans:system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  --serif:Charter,"Bitstream Charter","Iowan Old Style",Georgia,serif;
  --mono:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.6 var(--sans)}
.wrap{max-width:1080px;margin:0 auto;padding:0 24px}
a{color:var(--blue);text-underline-offset:2px}

/* retired chrome: the flat nav the July 28, 2026 navigation pass replaced.
   Kept so a page cached before that pass still styles while the ten-minute
   GitHub Pages cache turns over. Safe to remove in any later pass. */
.top{border-bottom:1px solid var(--hair);position:sticky;top:0;background:var(--bg);z-index:30}
.top .wrap{display:flex;gap:26px;height:54px;align-items:center}
.top .brand{margin-right:auto;display:inline;white-space:normal}
.top .brand b{color:var(--blue);font-weight:650}
.top nav{margin-left:auto;display:flex;gap:4px;flex-wrap:wrap}
.top nav a{font:500 13.5px var(--sans);color:var(--ink2);text-decoration:none;padding:6px 10px;border-radius:4px}
.top nav a:hover{background:var(--wash);color:var(--ink)}
.top nav a[aria-current]{color:var(--blue);font-weight:650;background:var(--bluewash)}

/* chrome: the shared menu. The markup is identical on every page; tools/check-site.py enforces it. */
.topbar{border-bottom:1px solid var(--hair);position:sticky;top:0;background:var(--bg);z-index:30}
.topbar .inner{max-width:1080px;margin:0 auto;padding:0 24px;min-height:54px;display:flex;align-items:center;gap:12px}
.brand{font:650 14px var(--sans);color:var(--ink);text-decoration:none;letter-spacing:.01em;margin-right:auto;display:flex;align-items:center;gap:8px;white-space:nowrap}
.brand .dot{width:8px;height:8px;border-radius:50%;background:var(--blue)}
.tnav{display:flex;gap:2px;align-items:center}
.tnav a{font:500 13.5px var(--sans);color:var(--ink2);text-decoration:none;padding:6px 10px;border-radius:4px;white-space:nowrap}
.tnav a:hover{background:var(--wash);color:var(--ink)}
.tnav a.on,.tnav a[aria-current]{color:var(--blue);font-weight:650;background:var(--bluewash)}
.navgrp{position:relative}
.navgrp>summary{list-style:none;cursor:pointer;font:500 13.5px var(--sans);color:var(--ink2);padding:6px 10px;border-radius:4px;display:inline-flex;align-items:center;gap:5px;white-space:nowrap}
.navgrp>summary::-webkit-details-marker{display:none}
.navgrp>summary:hover,.navgrp[open]>summary{background:var(--wash);color:var(--ink)}
.navgrp>summary.on{color:var(--blue);font-weight:650;background:var(--bluewash)}
.navgrp .caret{font-size:10px;opacity:.7}
.navgrp .tdrop-menu{position:absolute;top:calc(100% + 6px);left:0;background:var(--bg);border:1px solid var(--ink2);border-radius:4px;box-shadow:0 10px 30px rgba(22,24,29,.14);padding:6px;min-width:280px;display:flex;flex-direction:column;gap:2px;z-index:40}
.navgrp[data-navgrp="docs"] .tdrop-menu{left:auto;right:0}
.navgrp .tdrop-menu a{font:500 13.5px var(--sans);color:var(--ink);text-decoration:none;padding:8px 10px;border-radius:4px;white-space:normal;line-height:1.35}
.navgrp .tdrop-menu a:hover{background:var(--wash)}
.navgrp .tdrop-menu a.on,.navgrp .tdrop-menu a[aria-current]{background:var(--bluewash);color:var(--blue)}
.navgrp .tdrop-menu a .sub{display:block;font:400 11.5px var(--sans);color:var(--faint);margin-top:2px}
.navcta{font:600 13.5px var(--sans);color:var(--blue);background:var(--bluewash);text-decoration:none;border:1px solid transparent;padding:6px 12px;border-radius:4px;white-space:nowrap}
.navcta:hover{border-color:var(--blue)}
.hamburger{display:none;background:none;border:1px solid var(--hair);border-radius:4px;padding:4px 10px;font-size:16px;line-height:1;color:var(--ink);cursor:pointer}
@media(max-width:860px){
  .topbar .inner{position:relative}
  .hamburger{display:block}
  .tnav{display:none;position:absolute;top:100%;left:0;right:0;flex-direction:column;align-items:stretch;background:var(--bg);border-bottom:1px solid var(--hair);box-shadow:0 18px 40px rgba(22,24,29,.14);padding:8px 24px 14px;gap:2px;max-height:82vh;overflow:auto;z-index:35}
  .tnav.open{display:flex}
  .navgrp{border-top:1px solid var(--hair)}
  .navgrp:first-of-type{border-top:none}
  .navgrp>summary{padding:11px 10px;display:flex}
  .navgrp .caret{margin-left:auto}
  .navgrp .tdrop-menu{position:static;box-shadow:none;border:none;padding:2px 0 8px 10px;min-width:0}
  .navcta{text-align:left;margin-top:8px}
}

.foot{border-top:1px solid var(--hair);margin-top:80px}
.foot .wrap{padding:22px 24px 34px;font-size:12.5px;color:var(--faint);display:flex;gap:26px;flex-wrap:wrap}
.foot a{color:var(--ink2)}

/* page head */
.head{padding:42px 0 10px}
.kicker{font:600 11px var(--mono);letter-spacing:.16em;color:var(--faint);text-transform:uppercase;margin:0 0 12px}
.kicker b{color:var(--open);font-weight:600}
h1{font:700 clamp(26px,3.6vw,34px)/1.15 var(--sans);letter-spacing:-.015em;margin:0 0 8px}
.lede{font-size:16.5px;color:var(--ink2);max-width:60ch;margin:0}
.stamp{font:12px var(--mono);color:var(--faint);margin:12px 0 0}

section{margin:40px 0}
h2{font:650 19px/1.3 var(--sans);letter-spacing:-.01em;margin:0 0 8px}
h3{font:650 16px/1.4 var(--sans);margin:0 0 4px}
p{margin:0 0 12px;max-width:64ch}
.seclabel{font:600 10.5px var(--mono);letter-spacing:.16em;text-transform:uppercase;color:var(--faint);margin:0 0 4px}

/* status marks: always the word beside the color */
.mark{display:inline-flex;align-items:center;gap:6px;font:650 10.5px var(--sans);letter-spacing:.08em;text-transform:uppercase;padding:4px 9px;border-radius:3px}
.mark::before{content:"";width:6px;height:6px;border-radius:50%;background:currentColor}
.mark.open{color:var(--open);background:var(--openwash)}
.mark.settled{color:var(--settled);background:var(--settledwash)}
.mark.defect{color:var(--defect);background:var(--defectwash)}
.mark.gray{color:var(--ink2);background:var(--wash)}
.mark.blue{color:var(--blue);background:var(--bluewash)}

/* verbatim rule text: serif on wash, cited */
.verbatim{font:16px/1.75 var(--serif);background:var(--wash);border-left:3px solid var(--ink);padding:14px 18px;margin:12px 0}
.verbatim p{max-width:none}
.vsrc{font:11.5px var(--mono);color:var(--faint);margin-top:8px}
.vsrc a{color:var(--ink2)}

/* data tables */
table.data{border-collapse:collapse;width:100%;font-size:14px}
table.data th{font:600 10.5px var(--mono);letter-spacing:.12em;text-transform:uppercase;color:var(--faint);text-align:left;padding:8px 12px 8px 0;border-bottom:1.5px solid var(--ink)}
table.data td{padding:9px 12px 9px 0;border-bottom:1px solid var(--hair);vertical-align:top}
td.num,th.num{text-align:right;font-variant-numeric:tabular-nums}
.sect{font:12px var(--mono);color:var(--ink2);white-space:nowrap}

/* citation popover: hover opens, leaving closes, click opens the source in a new tab */
.cite{position:relative;display:inline}
.cite > a{font:600 10.5px var(--sans);color:var(--blue);text-decoration:none;vertical-align:super;line-height:0;padding:0 1px}
.cite .pop{position:absolute;left:50%;transform:translateX(-50%);bottom:calc(100% + 8px);width:300px;background:var(--ink);color:#F2F4F8;font:12.5px/1.55 var(--sans);padding:10px 13px;border-radius:4px;visibility:hidden;opacity:0;transition:opacity .12s;z-index:40}
.cite .pop b{color:#fff}
.cite .pop .go{display:block;margin-top:6px;font:11px var(--mono);color:#9FB2E8}
.cite:hover .pop{visibility:visible;opacity:1}
.cite .pop::after{content:"";position:absolute;top:100%;left:50%;margin-left:-5px;border:5px solid transparent;border-top-color:var(--ink)}

/* fixtures: dated one-line rows */
.fix{display:flex;gap:16px;align-items:baseline;padding:9px 0;border-top:1px solid var(--hair);font-size:14.5px}
.fix:first-of-type{border-top:1.5px solid var(--ink)}
.fix b{font:600 12px var(--mono);white-space:nowrap;color:var(--ink)}
.fix .what{color:var(--ink2)}
.fix .what a{white-space:nowrap}

.grid2{display:grid;grid-template-columns:1fr 1fr;gap:32px}
@media(max-width:820px){.grid2{grid-template-columns:1fr}}
.note{border-left:3px solid var(--blue);background:var(--bluewash);padding:12px 16px;font-size:14px;margin:14px 0}
.note.open{border-color:var(--open);background:var(--openwash)}
.note.defect{border-color:var(--defect);background:var(--defectwash)}

/* Citations: the source opens on hover, closes on leave, and the click opens it in a new tab */
a[data-cite]{position:relative}
a[data-cite]:hover::after,a[data-cite]:focus-visible::after{
  content:attr(data-cite);position:absolute;left:0;bottom:calc(100% + 7px);z-index:40;
  width:max-content;max-width:min(320px,72vw);white-space:normal;
  font:500 11.5px/1.5 var(--mono);letter-spacing:.01em;color:var(--ink);text-align:left;
  background:var(--bg);border:1px solid var(--ink2);border-radius:4px;padding:7px 10px;
  pointer-events:none}
a.pdf[data-cite]:hover::after,a.pdf[data-cite]:focus-visible::after{left:auto;right:0}

/* Provenance: the source-document chain and the per-page revision log,
   one collapsed details block at the end of main on every content page,
   generated by tools/sync-provenance.py. The restored pages carry their
   own copy of these rules in their page stylesheets. */
.prov{margin:72px 0 0;border-top:1px solid var(--hair)}
.prov>summary{list-style:none;cursor:pointer;padding:14px 0;display:flex;align-items:center;gap:10px;font:500 12.5px var(--mono);color:var(--faint)}
.prov>summary::-webkit-details-marker{display:none}
.prov>summary:hover{color:var(--ink2)}
.prov .provchev{margin-left:auto;font-size:10px;transition:transform .15s}
.prov[open] .provchev{transform:rotate(90deg)}
.provbody{padding:2px 0 10px}
.provsec{margin-top:16px}
.provk{font:600 11px var(--mono);letter-spacing:.09em;text-transform:uppercase;color:var(--faint);margin:0 0 8px}
.provsec .cd{font:12.5px var(--mono);color:var(--faint);margin:0}
.provsec .cn{font-size:14.5px;font-weight:650;color:var(--ink);margin:2px 0 0}
.provsec .cw{font-size:13.5px;color:var(--ink2);line-height:1.55;margin:6px 0 0}
.provsec .curflag{display:inline-block;font:600 10px var(--mono);text-transform:uppercase;letter-spacing:.05em;color:var(--settled);background:var(--settledwash);border-radius:20px;padding:2px 8px;margin-left:7px;vertical-align:1px}
.revs{list-style:none;margin:0;padding:0}
.revs li{font-size:13.5px;color:var(--ink2);line-height:1.55;padding:8px 0;border-top:1px solid var(--hair)}
.revs li:first-child{border-top:none;padding-top:0}
.revs b{color:var(--ink);font-weight:650}