/* Breakthrough Modeling (BTM) — site.css. No-nonsense, structure-first. Light + dark. */
:root{
  --bg:#ffffff; --fg:#14171a; --muted:#5b6570; --line:#e6e9ec;
  --accent:#2058b8; --accent-soft:#2058b814; --card:#f6f8fb; --code:#eef2f6;
  --max:940px;
}
@media (prefers-color-scheme:dark){
  :root{ --bg:#0d1015; --fg:#e8ecef; --muted:#9aa6b0; --line:#222833;
    --accent:#6ea0f0; --accent-soft:#6ea0f01a; --card:#141922; --code:#161c25; }
}
:root[data-theme="light"]{ --bg:#ffffff;--fg:#14171a;--muted:#5b6570;--line:#e6e9ec;--accent:#2058b8;--accent-soft:#2058b814;--card:#f6f8fb;--code:#eef2f6; }
:root[data-theme="dark"]{ --bg:#0d1015;--fg:#e8ecef;--muted:#9aa6b0;--line:#222833;--accent:#6ea0f0;--accent-soft:#6ea0f01a;--card:#141922;--code:#161c25; }

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--fg);
  font:17px/1.6 -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  -webkit-font-smoothing:antialiased;}
.wrap{max-width:var(--max);margin:0 auto;padding:0 22px}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}
h1,h2,h3{line-height:1.2;letter-spacing:-.01em;font-weight:700}
h1{font-size:clamp(2rem,5vw,3.1rem);margin:.2em 0 .3em}
h2{font-size:clamp(1.4rem,3vw,1.9rem);margin:2.4rem 0 .6rem}
h3{font-size:1.15rem;margin:1.6rem 0 .4rem}
p{margin:.7em 0}
strong{font-weight:650}
code{background:var(--code);padding:.12em .38em;border-radius:5px;font-size:.9em;
  font-family:ui-monospace,"SF Mono",Menlo,Consolas,monospace}

/* header */
header.site{border-bottom:1px solid var(--line);position:sticky;top:0;z-index:10;
  background:color-mix(in srgb,var(--bg) 88%,transparent);backdrop-filter:blur(8px)}
header.site .wrap{display:flex;align-items:center;justify-content:space-between;height:60px}
.brand{font-weight:800;color:var(--fg);letter-spacing:-.02em;font-size:1.05rem}
.brand .abbr{color:var(--accent)}
nav.main a{color:var(--muted);margin-left:20px;font-size:.93rem;font-weight:500}
nav.main a:hover{color:var(--fg);text-decoration:none}
nav.main a.cta{color:var(--accent);font-weight:600}
@media(max-width:680px){nav.main a{margin-left:12px;font-size:.82rem}
  nav.main a:not(.cta){display:none}}

/* hero */
.hero{padding:72px 22px 44px}
.eyebrow{display:inline-block;color:var(--accent);background:var(--accent-soft);
  font-weight:650;font-size:.82rem;letter-spacing:.02em;text-transform:uppercase;
  padding:5px 12px;border-radius:999px;margin-bottom:18px}
.hero .sub{font-size:clamp(1.05rem,2.2vw,1.3rem);color:var(--muted);max-width:640px;margin:.6em 0 0}
.hero .formula{margin-top:26px;font-size:.95rem;color:var(--muted);
  border-left:3px solid var(--accent);padding-left:14px}
.hero-img{display:block;width:100%;max-width:100%;height:auto;margin:38px 0 0;
  border:1px solid var(--line);border-radius:14px}
.section-img{display:block;width:100%;height:auto;margin:0;
  border:1px solid var(--line);border-radius:12px}
.fig{margin:26px 0}
.fig figcaption{margin-top:9px;font-size:.88rem;color:var(--muted);text-align:center}

/* sections */
section{padding:12px 0}
section.wrap{padding-top:8px;padding-bottom:8px}
.lead{font-size:1.12rem;color:var(--fg)}
.muted{color:var(--muted)}

/* the arc / steps */
.arc{display:flex;flex-wrap:wrap;gap:10px;margin:22px 0}
.arc .step{flex:1;min-width:120px;background:var(--card);border:1px solid var(--line);
  border-radius:12px;padding:14px 16px}
.arc .step .n{color:var(--accent);font-weight:700;font-size:.8rem;text-transform:uppercase;letter-spacing:.04em}
.arc .step h4{margin:.3em 0 .2em;font-size:1rem}
.arc .step p{margin:0;font-size:.9rem;color:var(--muted)}

/* compare table */
.cmp{width:100%;border-collapse:collapse;margin:18px 0;font-size:.95rem}
.cmp th,.cmp td{text-align:left;padding:10px 12px;border-bottom:1px solid var(--line);vertical-align:top}
.cmp th{color:var(--muted);font-weight:600;font-size:.82rem;text-transform:uppercase;letter-spacing:.03em}
.cmp .old{color:var(--muted)}
.cmp .new{font-weight:600}
.cmp-wrap{overflow-x:auto}

/* callout */
.callout{background:var(--card);border:1px solid var(--line);border-left:3px solid var(--accent);
  border-radius:10px;padding:18px 20px;margin:22px 0}
.callout p:first-child{margin-top:0}
.callout p:last-child{margin-bottom:0}

/* cards */
.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:14px;margin:20px 0}
.card{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:18px 20px}
.card h3{margin:0 0 .3em}
.card p{margin:0;color:var(--muted);font-size:.94rem}

/* cta */
.cta-row{display:flex;flex-wrap:wrap;gap:12px;margin:30px 0}
.btn{display:inline-block;background:var(--accent);color:#fff;font-weight:600;
  padding:11px 20px;border-radius:10px;font-size:.95rem}
.btn:hover{text-decoration:none;filter:brightness(1.08)}
.btn.ghost{background:transparent;color:var(--accent);border:1px solid var(--accent)}

/* footer */
footer{border-top:1px solid var(--line);margin-top:56px;padding:28px 0 48px;color:var(--muted);font-size:.9rem}
footer a{color:var(--muted);text-decoration:underline}
hr{border:none;border-top:1px solid var(--line);margin:34px 0}
.badge{display:inline-block;background:var(--accent-soft);color:var(--accent);
  font-size:.72rem;font-weight:700;padding:3px 9px;border-radius:999px;letter-spacing:.04em}