:root{
  --paper:#ffffff; --paper2:#f5f8fe; --ink:#0f172a; --ink2:#334155; --soft:#64748b;
  --rule:#e2e8f0; --rule2:#cbd5e1; --fx:#2563eb; --fx2:#1d4ed8; --fxsoft:#dbeafe;
  --gain:#15803d; --warn:#b45309;
  --head:'Libre Franklin',system-ui,-apple-system,Segoe UI,sans-serif;
  --read:'Source Serif 4',Georgia,'Times New Roman',serif;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--paper);color:var(--ink);font-family:var(--read);
  font-size:17px;line-height:1.66;-webkit-font-smoothing:antialiased}
.bfx-shell{max-width:1010px;margin:0 auto;padding:0 24px}
a{color:var(--fx2);text-decoration:none}
a:hover{text-decoration:underline}
h1,h2,h3,h4{font-family:var(--head);color:var(--ink);line-height:1.18;letter-spacing:-.014em;font-weight:700}
h2{font-size:clamp(1.4rem,2.6vw,1.9rem);margin:0 0 .45em}
h3{font-size:1.12rem;margin:1.5em 0 .35em}
p{margin:0 0 1em}
.bfx-dim{color:var(--soft)}
section{padding:46px 0}
section + section{border-top:1px solid var(--rule)}
.bfx-eyebrow{font-family:var(--head);font-weight:600;font-size:.72rem;letter-spacing:.18em;
  text-transform:uppercase;color:var(--fx);margin-bottom:13px}
/* masthead */
.bfx-top{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.92);backdrop-filter:blur(8px);
  border-bottom:1px solid var(--rule);display:flex;align-items:center;justify-content:space-between;
  gap:18px;padding:13px 24px}
.bfx-brand{display:flex;align-items:center;gap:10px;font-family:var(--head);font-weight:800;
  color:var(--ink);font-size:1rem;letter-spacing:-.02em}
.bfx-brand .pip{display:inline-block;width:11px;height:11px;border-radius:50%;background:var(--fx);
  box-shadow:0 0 0 4px var(--fxsoft)}
.bfx-links{display:flex;gap:22px;list-style:none;margin:0;padding:0;font-family:var(--head);
  font-size:.9rem;font-weight:500}
.bfx-links a{color:var(--ink2)}
.bfx-links a:hover{color:var(--fx);text-decoration:none}
.bfx-act{background:var(--fx);color:#fff!important;padding:8px 15px;border-radius:6px;
  font-weight:600;font-size:.84rem}
.bfx-act:hover{background:var(--fx2);text-decoration:none}
.bfx-burger{display:none;background:none;border:0;cursor:pointer;width:32px;height:26px}
.bfx-burger span{display:block;height:2px;background:var(--ink);margin:5px 0;border-radius:2px}
.bfx-drawer{display:none;flex-direction:column;background:var(--paper2);border-bottom:1px solid var(--rule)}
.bfx-drawer a{padding:13px 24px;border-bottom:1px solid var(--rule);font-family:var(--head);
  font-weight:500;color:var(--ink)}
.bfx-drawer.open{display:flex}
/* masthead hero */
.bfx-lede{background:linear-gradient(180deg,var(--paper2),var(--paper));padding:62px 0 44px;
  border-bottom:1px solid var(--rule)}
.bfx-kick{font-family:var(--head);font-weight:600;font-size:.76rem;letter-spacing:.16em;
  text-transform:uppercase;color:var(--fx)}
.bfx-lede h1{font-size:clamp(2rem,4.6vw,3.05rem);margin:.3em 0 .3em;letter-spacing:-.025em}
.bfx-stand{font-size:1.16rem;color:var(--ink2);max-width:63ch}
.bfx-quotes{display:flex;flex-wrap:wrap;gap:9px;margin-top:26px;font-family:var(--head);font-size:.82rem}
.bfx-q{border:1px solid var(--rule2);background:#fff;border-radius:999px;padding:7px 14px;color:var(--ink2)}
.bfx-q b{color:var(--fx2);font-weight:700}
.bfx-go{display:inline-block;margin-top:28px;background:var(--fx);color:#fff;font-family:var(--head);
  font-weight:700;padding:13px 22px;border-radius:8px;font-size:.95rem}
.bfx-go:hover{background:var(--fx2);text-decoration:none}
/* blocks */
.bfx-lead{font-size:1.08rem;color:var(--ink2)}
.bfx-sheet{background:#fff;border:1px solid var(--rule);border-radius:13px;padding:24px 26px;margin:20px 0;
  box-shadow:0 1px 2px rgba(15,23,42,.04)}
.bfx-sheet.pick{border-color:#bfd3fb;background:linear-gradient(180deg,#fbfdff,#fff);
  box-shadow:0 6px 24px -16px rgba(37,99,235,.5)}
.bfx-stamp{font-family:var(--head);font-weight:700;font-size:.7rem;letter-spacing:.16em;
  text-transform:uppercase;color:var(--fx);background:var(--fxsoft);display:inline-block;
  padding:5px 11px;border-radius:5px}
.bfx-cols{display:grid;gap:18px}
@media(min-width:730px){.bfx-cols.c3{grid-template-columns:repeat(3,1fr)}.bfx-cols.c2{grid-template-columns:1fr 1fr}}
.bfx-tile{background:#fff;border:1px solid var(--rule);border-radius:11px;padding:20px}
.bfx-tile h3{margin:0 0 .35em}
.bfx-num{font-family:var(--head);font-weight:700;font-size:.7rem;letter-spacing:.14em;
  text-transform:uppercase;color:var(--fx)}
ul.bfx-checks{list-style:none;padding:0;margin:16px 0}
ul.bfx-checks li{padding:11px 0 11px 30px;position:relative;border-bottom:1px solid var(--rule);color:var(--ink2)}
ul.bfx-checks li:before{content:"";position:absolute;left:4px;top:16px;width:13px;height:8px;
  border-left:2px solid var(--fx);border-bottom:2px solid var(--fx);transform:rotate(-45deg)}
.bfx-scroll{overflow-x:auto;margin:20px 0;border:1px solid var(--rule);border-radius:11px}
table{border-collapse:collapse;width:100%;font-family:var(--head);font-size:.92rem;min-width:540px}
caption{caption-side:bottom;font-family:var(--read);font-size:.82rem;color:var(--soft);
  text-align:left;padding:10px 14px}
th,td{padding:12px 15px;border-bottom:1px solid var(--rule);text-align:left}
thead th{background:var(--paper2);font-size:.7rem;letter-spacing:.08em;text-transform:uppercase;
  color:var(--soft);font-weight:600}
tbody tr:last-child td{border-bottom:0}
td .up{color:var(--gain);font-weight:700}
.bfx-flag{font-weight:600;color:var(--fx2)}
.bfx-trail{font-family:var(--head);font-size:.78rem;color:var(--soft);padding:18px 0 0}
.bfx-trail a{color:var(--soft)}
.bfx-trail .div{margin:0 7px;opacity:.5}
.bfx-pagehd{padding:50px 0 30px;background:var(--paper2);border-bottom:1px solid var(--rule)}
.bfx-pagehd h1{font-size:clamp(1.85rem,3.7vw,2.5rem);margin:.18em 0 .2em;letter-spacing:-.02em}
.bfx-pagehd .bfx-stand{font-size:1.1rem}
.bfx-essay h3{color:var(--fx2)}
.bfx-essay code{font-family:ui-monospace,Menlo,monospace;font-size:.88em;background:var(--paper2);
  border:1px solid var(--rule);border-radius:5px;padding:1px 6px;color:var(--ink)}
.bfx-aside{font-family:var(--head);font-size:.9rem;color:var(--ink2);background:var(--paper2);
  border-left:3px solid var(--fx);border-radius:0 8px 8px 0;padding:13px 18px;margin:20px 0}
/* footer */
.bfx-foot{background:var(--ink);color:#cbd5e1;margin-top:0;padding:48px 0 34px}
.bfx-foot a{color:#cbd5e1}
.bfx-foot a:hover{color:#fff}
.bfx-foot .grid{display:grid;gap:26px}
@media(min-width:730px){.bfx-foot .grid{grid-template-columns:2.2fr 1fr 1fr 1fr}}
.bfx-foot .ttl{font-family:var(--head);font-weight:700;color:#fff;font-size:.74rem;letter-spacing:.12em;
  text-transform:uppercase;margin-bottom:11px}
.bfx-foot .link{display:block;padding:4px 0;font-family:var(--head);font-size:.92rem}
.bfx-foot .blurb{color:#94a3b8;max-width:40ch;font-size:.96rem}
.bfx-fine{color:#64748b;font-size:.82rem;border-top:1px solid #1e293b;margin-top:26px;padding-top:18px}
.bfx-foot .markrow{display:flex;align-items:center;gap:10px;color:#fff;font-family:var(--head);
  font-weight:800;margin-bottom:12px}
.bfx-foot .markrow .pip{width:11px;height:11px;border-radius:50%;background:var(--fx);box-shadow:0 0 0 4px rgba(37,99,235,.25)}
/* worked-example dossier block: a numbered, bordered procedure card, distinct from .bfx-aside */
.bfx-worked{background:#fff;border:1px solid var(--rule);border-top:3px solid var(--fx);border-radius:11px;
  padding:22px 24px;margin:24px 0;box-shadow:0 1px 2px rgba(15,23,42,.05)}
.bfx-worked .label{font-family:var(--head);font-weight:700;font-size:.7rem;letter-spacing:.15em;
  text-transform:uppercase;color:var(--fx);background:var(--fxsoft);display:inline-block;padding:5px 11px;
  border-radius:5px;margin-bottom:14px}
.bfx-worked ol{margin:0;padding-left:22px}
.bfx-worked ol li{padding:7px 0;color:var(--ink2)}
.bfx-worked ol li b{color:var(--ink)}
.bfx-worked .ledger{font-family:ui-monospace,Menlo,monospace;font-size:.86em;color:var(--ink);
  background:var(--paper2);border:1px solid var(--rule);border-radius:5px;padding:1px 7px;white-space:nowrap}
/* on-brand inline diagram frame (light sheet, FX blue) */
figure.bfx-fig{margin:26px 0;background:var(--paper2);border:1px solid var(--rule);border-radius:13px;
  padding:20px 20px 14px}
figure.bfx-fig svg{display:block;width:100%;height:auto;max-width:780px;margin:0 auto}
figure.bfx-fig figcaption{font-family:var(--head);font-size:.82rem;color:var(--soft);
  text-align:center;margin-top:12px;line-height:1.5}
.bfx-fig .f-box{fill:#ffffff;stroke:#bfd3fb;stroke-width:1.3}
.bfx-fig .f-rail{stroke:var(--fx);stroke-width:1.7;fill:none}
.bfx-fig .f-head{font-family:'Libre Franklin',sans-serif;font-size:11.5px;fill:#0f172a;font-weight:700}
.bfx-fig .f-sub{font-family:'Libre Franklin',sans-serif;font-size:9.5px;fill:#64748b}
.bfx-fig .f-axis{font-family:'Libre Franklin',sans-serif;font-size:10px;fill:#64748b}
.bfx-fig .f-yes{fill:#15803d;font-family:'Libre Franklin',sans-serif;font-size:13px;font-weight:700}
.bfx-fig .f-no{fill:#b91c1c;font-family:'Libre Franklin',sans-serif;font-size:13px;font-weight:700}
/* grade-bar table accent */
.bfx-gbar{font-family:var(--head);font-weight:700;color:var(--fx2)}
/* related rail at the foot of a page */
.bfx-related{margin:34px 0 0;border-top:1px solid var(--rule);padding-top:22px}
.bfx-related .ttl{font-family:var(--head);font-weight:700;font-size:.74rem;letter-spacing:.15em;
  text-transform:uppercase;color:var(--fx);margin-bottom:14px}
.bfx-related .rows{display:grid;gap:11px}
@media(min-width:620px){.bfx-related .rows{grid-template-columns:1fr 1fr}}
.bfx-related a.row{display:block;border:1px solid var(--rule);border-radius:9px;padding:13px 15px;
  background:#fff;color:var(--ink2)}
.bfx-related a.row:hover{border-color:#bfd3fb;text-decoration:none;box-shadow:0 4px 14px -10px rgba(37,99,235,.5)}
.bfx-related a.row b{color:var(--fx2);display:block;font-family:var(--head);font-size:.96rem;margin-bottom:2px}
.bfx-related a.row span{color:var(--soft);font-size:.86rem;font-family:var(--head)}
@media(max-width:729px){.bfx-links{display:none}.bfx-burger{display:block}}

/* a11y + responsive polish */
:focus-visible{outline:2px solid currentColor;outline-offset:3px;border-radius:3px}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{animation-duration:.01ms !important;transition-duration:.01ms !important}}
@media(max-width:719px){table{min-width:0}th,td{padding:8px 10px}}