/* VentiFlux Tools - shared stylesheet (brand-matched to ventiflux.com) */
:root{
  --navy:#0d4079; --navy-deep:#0a3261; --copper:#c85f2f; --copper-soft:#e5edf5;
  --paper:#f3f5f4; --ink:#142d38; --muted:#53656d; --surface:#ffffff;
  --line:#cbd5d3; --mint:#b9dae1;
  --font-sans:"IBM Plex Sans",-apple-system,"Segoe UI",sans-serif;
  --font-serif:"Newsreader",Georgia,serif;
  --font-mono:"IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,monospace;
  --shadow:0 2px 14px rgba(13,64,121,.08);
  --radius:14px;
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{font-family:var(--font-sans);color:var(--ink);background:var(--paper);line-height:1.7;-webkit-font-smoothing:antialiased}
a{color:var(--navy)}
img{max-width:100%}
.wrap{max-width:1180px;margin:0 auto;padding:0 24px}

/* ---------- top bar ---------- */
.vf-topbar{position:sticky;top:0;z-index:50;background:var(--surface);border-bottom:1px solid var(--line)}
.vf-topbar .wrap{display:flex;align-items:center;justify-content:space-between;height:68px}
.brand{display:flex;align-items:center;gap:12px;text-decoration:none;color:var(--navy);font-weight:700;font-size:1.25rem;letter-spacing:.02em}
.brand img{height:38px;width:auto}
.brand small{display:block;font-size:.68rem;font-weight:500;color:var(--muted);letter-spacing:.14em;text-transform:uppercase}
.vf-nav{display:flex;gap:26px;align-items:center}
.vf-nav a{text-decoration:none;color:var(--ink);font-weight:500;font-size:.95rem}
.vf-nav a:hover{color:var(--copper)}
.vf-nav a.active{color:var(--navy);font-weight:700}
.vf-nav .nav-cta{background:var(--copper);color:#fff;padding:10px 20px;border-radius:999px;font-weight:600}
.vf-nav .nav-cta:hover{background:var(--navy);color:#fff}

/* ---------- hero ---------- */
.hero{background:linear-gradient(135deg,var(--navy) 0%,var(--navy-deep) 60%,#123f74 100%);color:#fff;padding:72px 0 64px;position:relative;overflow:hidden}
.hero::after{content:"";position:absolute;right:-120px;top:-120px;width:420px;height:420px;border-radius:50%;background:radial-gradient(circle,rgba(200,95,47,.35),transparent 70%)}
.kicker{display:inline-block;font-size:.75rem;font-weight:700;letter-spacing:.18em;text-transform:uppercase;color:#ffd9a8;margin-bottom:14px}
.hero h1{font-family:var(--font-serif);font-size:clamp(2rem,4.5vw,3.1rem);line-height:1.15;font-weight:600;max-width:820px;margin-bottom:16px}
.hero p.lead{font-size:1.08rem;color:#dbe7f3;max-width:760px}
.hero .back-link{display:inline-block;color:#ffd9a8;text-decoration:none;font-size:.9rem;font-weight:600;margin-bottom:18px}
.hero .back-link:hover{color:#fff}

/* ---------- tool cards (hub) ---------- */
.tools-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(320px,1fr));gap:24px;max-width:1180px;margin:0 auto;padding:56px 24px 80px}
.tool-card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:30px;box-shadow:var(--shadow);display:flex;flex-direction:column;text-decoration:none;color:var(--ink);transition:transform .15s ease,box-shadow .15s ease}
.tool-card:hover{transform:translateY(-3px);box-shadow:0 8px 28px rgba(13,64,121,.14)}
.tool-card .tool-tag{font-size:.72rem;font-weight:700;letter-spacing:.14em;text-transform:uppercase;color:var(--copper);margin-bottom:10px}
.tool-card h2{font-family:var(--font-serif);font-size:1.45rem;color:var(--navy);margin-bottom:10px;line-height:1.3}
.tool-card p{font-size:.96rem;color:var(--muted);flex:1;margin-bottom:18px}
.tool-card .tool-go{font-weight:700;color:var(--navy)}
.tool-card:hover .tool-go{color:var(--copper)}
.tool-card.soon{opacity:.75}
.tool-card.soon .tool-go{color:var(--muted)}

/* ---------- calculator layout ---------- */
.calc-layout{max-width:1180px;margin:0 auto;padding:48px 24px 80px;display:grid;grid-template-columns:1fr 380px;gap:32px;align-items:start}
.calc-main{min-width:0}
.calc-card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:34px;box-shadow:var(--shadow);margin-bottom:28px}
.calc-card h2{font-family:var(--font-serif);font-size:1.5rem;color:var(--navy);margin-bottom:6px}
.calc-card .calc-sub{color:var(--muted);font-size:.95rem;margin-bottom:24px}
.field-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px;margin-bottom:24px}
.field{display:flex;flex-direction:column;gap:6px}
.field.full{grid-column:1/-1}
.field label{font-size:.85rem;font-weight:600;color:var(--navy)}
.field label .unit{font-weight:400;color:var(--muted)}
.field input,.field select{font-family:var(--font-sans);font-size:1rem;padding:11px 14px;border:1px solid var(--line);border-radius:8px;background:#fff;color:var(--ink)}
.field input:focus,.field select:focus{outline:2px solid var(--copper);border-color:var(--copper)}
.field .hint{font-size:.8rem;color:var(--muted)}
.btn-row{display:flex;gap:12px;flex-wrap:wrap}
.btn{font-family:var(--font-sans);font-size:1rem;font-weight:700;padding:13px 30px;border-radius:999px;border:none;cursor:pointer}
.btn-primary{background:var(--copper);color:#fff}
.btn-primary:hover{background:var(--navy)}
.btn-ghost{background:transparent;color:var(--navy);border:2px solid var(--line)}
.btn-ghost:hover{border-color:var(--navy)}
.results{display:none;margin-top:28px;border-top:2px solid var(--copper-soft);padding-top:24px}
.results.show{display:block}
.results h3{font-size:.82rem;letter-spacing:.12em;text-transform:uppercase;color:var(--navy);margin-bottom:16px}
.result-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.result{background:var(--paper);border-radius:10px;padding:16px 18px}
.result.highlight{background:var(--navy);color:#fff}
.result.highlight .result-label{color:#bcd2ea}
.result-label{font-size:.78rem;font-weight:600;letter-spacing:.06em;text-transform:uppercase;color:var(--muted);margin-bottom:4px}
.result-value{font-family:var(--font-mono);font-size:1.35rem;font-weight:600;color:var(--navy)}
.result.highlight .result-value{color:#fff}
.result-note{font-size:.82rem;color:var(--muted);margin-top:4px}
.calc-error{display:none;background:#fdecea;border:1px solid #f5b7b1;color:#a93226;border-radius:10px;padding:14px 18px;margin-top:18px;font-size:.95rem}
.calc-error.show{display:block}

/* ---------- Richardson page additions ---------- */
.group-title{font-size:.82rem;letter-spacing:.1em;text-transform:uppercase;color:var(--navy);margin:22px 0 12px}
.group-title:first-of-type{margin-top:6px}
.result-flag{display:none;margin-top:16px;border-radius:10px;padding:14px 18px;font-size:.92rem;background:#eaf4ea;border:1px solid #a9cfa9;color:#1e6b1e}
.result-flag.show{display:block}
.result-flag.warn{background:#fef6e7;border-color:#f0c96a;color:#8a5a17}

/* ---------- method / explainer ---------- */
.method{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:34px;box-shadow:var(--shadow);margin-bottom:28px}
.method h2{font-family:var(--font-serif);font-size:1.5rem;color:var(--navy);margin-bottom:16px}
.method h3{font-size:.85rem;letter-spacing:.1em;text-transform:uppercase;color:var(--navy);margin:26px 0 10px}
.method p{margin-bottom:14px;font-size:.98rem}
.method ol,.method ul{margin:0 0 16px 22px;font-size:.98rem}
.method li{margin-bottom:6px}
.equation{background:var(--paper);border-left:4px solid var(--copper);border-radius:0 10px 10px 0;padding:16px 20px;margin:18px 0;font-family:var(--font-mono);font-size:.95rem;overflow-x:auto}
.equation .eq-label{font-family:var(--font-sans);font-size:.8rem;color:var(--muted);margin-bottom:6px}
.symbols{font-size:.88rem;margin:8px 0 0}
.symbols dt{display:inline;font-weight:700;color:var(--navy);font-family:var(--font-mono);font-size:.85rem}
.symbols dd{display:inline;margin:0;color:var(--muted)}
.symbols dd::after{content:"";display:block;margin-bottom:4px}
.references{margin-top:10px}
.references li{font-size:.9rem;color:var(--muted);margin-bottom:6px}

/* ---------- sidebar ---------- */
.calc-side{position:sticky;top:92px}
.side-card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:24px;box-shadow:var(--shadow);margin-bottom:20px}
.side-card h3{font-size:.8rem;letter-spacing:.12em;text-transform:uppercase;color:var(--navy);margin-bottom:12px}
.side-card p,.side-card li{font-size:.9rem;color:var(--muted)}
.side-card ul{margin-left:18px}
.side-card li{margin-bottom:8px}
.side-card a{font-weight:600}
.disclaimer{background:#fff8f0;border:1px solid #f0d9b5;border-radius:var(--radius);padding:24px}
.disclaimer h3{color:#8a5a17}
.disclaimer p{font-size:.88rem;color:#6b5a3e}

/* ---------- footer ---------- */
.vf-footer{background:var(--navy);color:#cfe0f2;padding:44px 0;margin-top:0}
.vf-footer .wrap{display:flex;justify-content:space-between;gap:24px;flex-wrap:wrap;align-items:center}
.vf-footer p{font-size:.9rem;margin:0}
.vf-footer a{color:#fff;font-weight:600}

@media (max-width:900px){
  .calc-layout{grid-template-columns:1fr}
  .calc-side{position:static}
  .field-grid{grid-template-columns:1fr}
  .vf-nav{gap:16px}
  .vf-nav a:not(.nav-cta){display:none}
}