:root{
  --bg:#f6f8fa; --panel:#ffffff; --ink:#151b23; --muted:#5a6572; --line:#e6e9ee;
  --brand:#2f6bff; --brand-dark:#1f4fd6; --brand-soft:#eef4ff;
  --green:#12945a; --green-soft:#e2f6ec; --amber:#c47d09; --amber-soft:#fdf3dc;
  --red:#d63030; --red-soft:#fdeaea; --ink-code:#0d1526;
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  background:var(--bg);color:var(--ink);line-height:1.6;-webkit-font-smoothing:antialiased}
a{color:var(--brand);text-decoration:none}

/* ---- nav ---- */
.wrap{max-width:1200px;margin:0 auto;padding:0 20px}
header{background:var(--panel);border-bottom:1px solid var(--line);position:sticky;top:0;z-index:30}
.nav{display:flex;align-items:center;justify-content:space-between;height:60px;position:relative}
.logo{font-weight:800;font-size:19px;letter-spacing:-.4px;color:var(--ink)}
.logo b{color:var(--brand)}
.nav-links{display:flex;align-items:center;gap:4px;font-size:14px}
.nav-link{display:inline-flex;align-items:center;gap:5px;color:var(--muted);font-weight:600;
  padding:9px 13px;border-radius:9px;cursor:pointer;background:none;border:none;
  font-family:inherit;font-size:14px;letter-spacing:-.1px}
.nav-link:hover{color:var(--brand);background:var(--brand-soft)}
.nav-soon{display:inline-flex;align-items:center;gap:6px;color:#9aa4b2;font-weight:600;
  padding:9px 13px;font-size:14px;cursor:default}
.nav-soon .badge{font-size:10px;font-weight:700;color:var(--amber);background:var(--amber-soft);
  padding:2px 7px;border-radius:999px}
.nav-item{position:relative}
.dropdown{position:absolute;top:100%;left:0;min-width:300px;background:var(--panel);
  border:1px solid var(--line);border-radius:14px;box-shadow:0 18px 40px rgba(20,30,60,.14);
  padding:8px;margin-top:10px;opacity:0;visibility:hidden;transform:translateY(-6px);
  transition:all .16s ease;z-index:40}
.nav-item:hover .dropdown,.nav-item.open .dropdown{opacity:1;visibility:visible;transform:translateY(0)}
.dropdown::before{content:"";position:absolute;top:-8px;left:26px;width:14px;height:14px;
  background:var(--panel);border-left:1px solid var(--line);border-top:1px solid var(--line);transform:rotate(45deg)}
.drop-item{display:flex;align-items:center;gap:12px;padding:10px 12px;border-radius:10px;color:var(--ink)}
a.drop-item:hover{background:var(--brand-soft)}
.drop-item .ic{font-size:22px;flex:0 0 auto}
.di-txt{flex:1;min-width:0}
.di-txt b{display:block;font-size:14px}
.di-txt small{display:block;font-size:12px;color:var(--muted);margin-top:1px}
.drop-item.current{background:var(--brand-soft);outline:1px solid var(--brand)}
.drop-soon{font-size:10px;font-weight:700;color:var(--amber);background:var(--amber-soft);
  padding:2px 7px;border-radius:999px;flex:0 0 auto}
.nav-toggle{display:none;background:none;border:none;font-size:24px;line-height:1;color:var(--ink);cursor:pointer;padding:6px 8px}

/* ---- hero / sections ---- */
.hero{text-align:center;padding:46px 0 20px}
.hero .tagline{display:inline-block;font-size:12.5px;font-weight:700;color:var(--brand);
  background:var(--brand-soft);padding:5px 14px;border-radius:999px;margin-bottom:16px;letter-spacing:.2px}
.hero h1{font-size:34px;line-height:1.2;letter-spacing:-.8px;margin-bottom:12px}
.hero h1 span{color:var(--brand)}
.hero p{font-size:17px;color:var(--muted);max-width:640px;margin:0 auto}
@media(max-width:640px){.hero h1{font-size:26px}}
section{margin:42px 0}
h2.sec{font-size:23px;letter-spacing:-.4px;margin-bottom:6px;text-align:center}
.sec-sub{text-align:center;color:var(--muted);font-size:15px;margin-bottom:22px}

/* ---- platform switcher ---- */
.pm-switch{display:flex;flex-wrap:wrap;align-items:center;gap:8px;justify-content:center;margin:6px 0 4px}
.pm-switch-lbl{font-size:13px;color:var(--muted);font-weight:600;margin-right:4px}
.pm-pill{font-size:13px;font-weight:600;padding:7px 14px;border-radius:999px;border:1px solid var(--line);
  background:#fff;color:var(--muted);transition:all .12s}
.pm-pill:hover{border-color:var(--brand);color:var(--brand);background:var(--brand-soft)}
.pm-pill.active{background:var(--brand);border-color:var(--brand);color:#fff}

/* ---- calculator ---- */
.calc{background:var(--panel);border:1px solid var(--line);border-radius:18px;
  box-shadow:0 6px 24px rgba(20,30,60,.06);margin:22px 0;overflow:hidden}
.calc-head{padding:18px 24px;border-bottom:1px solid var(--line);display:flex;
  align-items:center;justify-content:space-between;flex-wrap:wrap;gap:12px}
.calc-head h2{font-size:17px}
.copy-btn{font-size:12.5px;font-weight:600;padding:7px 13px;border-radius:9px;border:1px solid var(--line);
  background:#fff;color:var(--brand);cursor:pointer;transition:all .15s;white-space:nowrap}
.copy-btn:hover{border-color:var(--brand);background:var(--brand-soft)}
.calc-body{display:grid;grid-template-columns:1fr 1fr;gap:0}
@media(max-width:760px){.calc-body{grid-template-columns:1fr}}
.inputs{padding:22px 24px;border-right:1px solid var(--line)}
@media(max-width:760px){.inputs{border-right:none;border-bottom:1px solid var(--line)}}
.field{margin-bottom:15px}
.field:last-child{margin-bottom:0}
label{display:block;font-size:13px;color:var(--ink);margin-bottom:5px;font-weight:600}
label .hint{font-weight:400;color:var(--muted);font-size:12px}
.in-wrap{position:relative}
.in-wrap .unit{position:absolute;right:12px;top:50%;transform:translateY(-50%);color:var(--muted);font-size:13px}
input[type=number],input[type=text],select{width:100%;padding:10px 12px;border:1px solid var(--line);border-radius:9px;font-size:15px;color:var(--ink);background:#fff}
input:focus,select:focus{outline:none;border-color:var(--brand);box-shadow:0 0 0 3px var(--brand-soft)}
.row3{display:grid;grid-template-columns:1fr 1fr 1fr;gap:10px}
.row2{display:grid;grid-template-columns:1fr 1fr;gap:10px}
@media(max-width:480px){.row3{grid-template-columns:1fr}.row2{grid-template-columns:1fr}}
.units-row{display:flex;align-items:center;justify-content:space-between;gap:10px;flex-wrap:wrap;margin-bottom:12px}
.units-row > label{margin:0}
.seg{display:inline-flex;background:var(--bg);border:1px solid var(--line);border-radius:9px;padding:3px;gap:2px}
.seg button{border:none;background:none;font:inherit;font-size:12.5px;font-weight:600;color:var(--muted);
  padding:6px 12px;border-radius:7px;cursor:pointer;transition:all .12s}
.seg button.active{background:#fff;color:var(--brand);box-shadow:0 1px 3px rgba(20,30,60,.12)}
.outputs{padding:22px 24px;background:#fbfcfe}
.metrics{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-bottom:12px}
.metric{background:#fff;border:1px solid var(--line);border-radius:11px;padding:12px 13px}
.metric .k{font-size:12px;color:var(--muted);margin-bottom:3px}
.metric .v{font-size:19px;font-weight:800;font-variant-numeric:tabular-nums;letter-spacing:-.3px}
.metric.big{background:var(--brand-soft);border-color:var(--brand)}
.metric.big .v{color:var(--brand-dark);font-size:22px}
.metric.good .v{color:var(--green)}
.metric.bad .v{color:var(--red)}
.metrics-note{font-size:12.5px;color:var(--muted);margin:-4px 0 14px;font-weight:600}
.breakdown{background:#fff;border:1px solid var(--line);border-radius:11px;padding:12px 14px;font-size:13.5px}
.breakdown .br{display:flex;justify-content:space-between;padding:5px 0;border-bottom:1px dashed var(--line)}
.breakdown .br:last-child{border-bottom:none}
.breakdown .br b{font-variant-numeric:tabular-nums}
.advisory{margin-top:14px;background:var(--green-soft);border:1px solid #bfe6d0;border-radius:11px;
  padding:12px 14px;font-size:13.5px;color:#0f5132;line-height:1.55}
.advisory div{margin:3px 0}
.caveat{font-size:12.5px;color:var(--muted);margin-top:6px}
.fba-presets{display:flex;gap:6px;flex-wrap:wrap;margin-top:6px}
.fba-presets button{font-size:11.5px;font-weight:600;padding:5px 10px;border-radius:8px;border:1px solid var(--line);background:#fff;color:var(--muted);cursor:pointer}
.fba-presets button:hover{border-color:var(--brand);color:var(--brand)}
.adv-toggle{font-size:12.5px;color:var(--brand);cursor:pointer;font-weight:600;user-select:none;margin-top:4px}
.adv{display:none;margin-top:10px;padding-top:10px;border-top:1px dashed var(--line)}
.adv.open{display:block}

/* ---- prose / steps / cards ---- */
.cluster{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}
@media(max-width:760px){.cluster{grid-template-columns:1fr 1fr}}
@media(max-width:480px){.cluster{grid-template-columns:1fr}}
.tool-card{background:var(--panel);border:1px solid var(--line);border-radius:13px;padding:18px;transition:all .15s;display:block}
.tool-card:hover{border-color:var(--brand);box-shadow:0 4px 14px rgba(20,30,60,.07);transform:translateY(-2px)}
.tool-card .ic{font-size:22px;margin-bottom:8px}
.tool-card h3{font-size:15px;color:var(--ink);margin-bottom:3px}
.tool-card p{font-size:13px;color:var(--muted)}
.tool-card .soon{font-size:11px;font-weight:700;color:var(--amber);background:var(--amber-soft);padding:2px 8px;border-radius:999px;display:inline-block;margin-top:8px}
.tool-card.live .soon{color:var(--green);background:var(--green-soft)}
.prose{background:var(--panel);border:1px solid var(--line);border-radius:14px;padding:26px 28px}
.prose h3{font-size:17px;margin:20px 0 8px}.prose h3:first-child{margin-top:0}
.prose p{color:var(--muted);margin:8px 0}
.prose ul{margin:8px 0 8px 20px}.prose li{color:var(--muted);margin:6px 0}
.prose b{color:var(--ink)}
.steps{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin:6px 0}
@media(max-width:640px){.steps{grid-template-columns:1fr 1fr}}
.step{background:var(--brand-soft);border-radius:11px;padding:14px;text-align:center}
.step .n{font-weight:800;color:var(--brand);font-size:18px}
.step .t{font-size:13px;color:var(--ink);font-weight:600;margin-top:4px}
details{background:var(--panel);border:1px solid var(--line);border-radius:11px;padding:0;margin:10px 0}
summary{padding:15px 18px;font-weight:600;font-size:15px;cursor:pointer;list-style:none;position:relative}
summary::-webkit-details-marker{display:none}
summary::after{content:"+";position:absolute;right:18px;color:var(--brand);font-weight:700;font-size:18px}
details[open] summary::after{content:"–"}
details .ans{padding:0 18px 15px;color:var(--muted);font-size:14px}

/* ---- tables / banner / toast / footer ---- */
table.ex{width:100%;border-collapse:collapse;margin:12px 0;font-size:14px}
table.ex th,table.ex td{border:1px solid var(--line);padding:9px 12px;text-align:left;vertical-align:top}
table.ex th{background:var(--brand-soft);color:var(--brand-dark);font-size:13px}
table.ex td:last-child{font-weight:700;color:var(--ink);font-variant-numeric:tabular-nums}
table.ex tr.hl td{background:var(--green-soft)}
table.ex tr.hl td:first-child{font-weight:700;color:var(--green)}
.ex-note{font-size:12.5px;color:var(--muted);margin-top:4px}
.toast{position:fixed;bottom:24px;left:50%;transform:translateX(-50%);background:var(--ink);color:#fff;
  padding:10px 18px;border-radius:10px;font-size:14px;font-weight:600;opacity:0;transition:opacity .2s;z-index:60;pointer-events:none}
.toast.show{opacity:1}
.banner{background:var(--brand-soft);border:1px solid var(--brand);border-radius:11px;padding:10px 14px;font-size:13px;color:var(--brand-dark);margin:0 0 14px;font-weight:600}
.hide{display:none}
.tbl-scroll{overflow-x:auto;-webkit-overflow-scrolling:touch;max-width:100%;margin:12px 0}
.calc-body>div{min-width:0}
.layout>*{min-width:0}
.tbl-scroll>table{margin-top:0;margin-bottom:0}
#compTable{min-width:540px}

footer{background:var(--panel);border-top:1px solid var(--line);margin-top:50px;padding:30px 0}
.foot-grid{display:flex;justify-content:space-between;flex-wrap:wrap;gap:20px}
.foot-brand{font-weight:800;font-size:17px}
.foot-brand b{color:var(--brand)}
.foot-brand p{font-size:13px;color:var(--muted);margin-top:6px;max-width:280px}
.foot-col h4{font-size:12px;text-transform:uppercase;letter-spacing:.5px;color:var(--muted);margin-bottom:10px}
.foot-col a{display:block;font-size:13.5px;color:var(--ink);margin:6px 0}
.foot-col a:hover{color:var(--brand)}
.copyright{text-align:center;font-size:12.5px;color:#9aa4b2;margin-top:24px;padding-top:18px;border-top:1px solid var(--line)}
.foot-col span.foot-ph{display:block;font-size:13.5px;color:#9aa4b2;margin:6px 0;cursor:default}

/* ---- mobile nav ---- */
@media(max-width:640px){
  .nav-links{display:none;position:absolute;top:60px;left:0;right:0;background:var(--panel);
    flex-direction:column;gap:0;padding:6px 14px 14px;border-bottom:1px solid var(--line);
    box-shadow:0 10px 24px rgba(20,30,60,.1);align-items:stretch}
  .nav-links.open{display:flex}
  .nav-link,.nav-soon{width:100%;text-align:left;padding:13px 8px;font-size:15px;border-radius:0}
  .nav-soon{border-bottom:1px solid var(--line)}
  .nav-item{position:static}
  .dropdown{position:static;opacity:1;visibility:visible;transform:none;box-shadow:none;
    border:none;margin:0;padding:0 0 6px 10px;min-width:auto;display:none}
  .nav-item.open .dropdown{display:block}
  .dropdown::before{display:none}
}

/* ---- Shopify detailed groups + visual breakdown ---- */
.grp-h{font-size:12px;font-weight:800;letter-spacing:.4px;text-transform:uppercase;color:var(--brand-dark);
  margin:14px 0 2px;padding-top:8px;border-top:1px solid var(--line)}
#revNote{font-size:12.5px;color:var(--muted);background:var(--brand-soft);border:1px solid var(--brand);
  border-radius:9px;padding:8px 11px;font-variant-numeric:tabular-nums}
#revNote b{color:var(--brand-dark)}
.stack{margin:10px 0 2px}
.stack-row{display:flex;height:18px;border-radius:5px;overflow:hidden;background:var(--line);min-width:100%}
.seg{height:100%;display:block;min-width:0}
.seg.net{box-shadow:inset 0 0 0 1px rgba(255,255,255,.4)}
.stack-leg{display:flex;flex-wrap:wrap;gap:4px 12px;margin-top:7px;font-size:11.5px;color:var(--muted)}
.stack-leg span{display:inline-flex;align-items:center;gap:5px;white-space:nowrap}
.stack-leg i{width:9px;height:9px;border-radius:2px;display:inline-block}
.monthly{margin-top:12px;background:#08311f;border:1px solid #0f5132;border-radius:11px;
  padding:11px 14px;font-size:14px;color:#d7f5e6;font-variant-numeric:tabular-nums}
.monthly b{color:#7dffc4;font-size:16px}