:root{
  --pine:#1e2b26; --pine2:#26382f; --paper:#faf6ef; --card:#ffffff;
  --ink:#23272a; --muted:#5d665f; --line:#e6ddcc; --line2:#efe8da;
  --orange:#e07b24; --orange-d:#c86414; --orange-soft:#fdf0e0;
  --steel:#2f5d50; --steel-soft:#e9f2ee; --amber-row:#fdf8ef;
  --radius:14px;
}
*{margin:0;padding:0;box-sizing:border-box}
html{background:var(--paper)}
body{font-family:'Inter',system-ui,sans-serif;color:var(--ink);background:var(--paper);-webkit-font-smoothing:antialiased}
h1,h2,h3,.brand-name{font-family:'Archivo',sans-serif}
.mono{font-family:'IBM Plex Mono',monospace}
.wrap{max-width:860px;margin:0 auto;padding:0 20px}
a{color:var(--steel);text-decoration:none}

/* header */
header{background:var(--pine);color:#f3efe6;position:relative}
.hbar{max-width:1100px;margin:0 auto;padding:14px 20px;display:flex;align-items:center;gap:28px}
.brand{display:flex;align-items:center;gap:11px;color:#fff}
.brand-mark{width:34px;height:34px;border-radius:8px;background:var(--orange);display:flex;align-items:center;justify-content:center;flex:none}
.brand-name{font-size:19px;font-weight:800;letter-spacing:.2px;line-height:1.05}
.brand-name small{display:block;font-family:'Inter';font-weight:500;font-size:10.5px;color:#c9cfc4;letter-spacing:1.6px;text-transform:uppercase}
nav.main{margin-left:auto;display:flex;gap:4px;align-items:center}
nav.main a{color:#e9e5d8;font-size:14.5px;font-weight:500;padding:8px 12px;border-radius:8px}
nav.main a.cta{background:var(--orange);color:#fff;font-weight:600}
.burger{display:none;margin-left:auto;background:none;border:1px solid #45534c;color:#fff;border-radius:8px;padding:7px 11px;font-size:16px}

/* hero */
.hero{text-align:center;padding:44px 0 8px}
.kicker{display:inline-block;background:var(--steel-soft);color:var(--steel);font-size:12px;font-weight:700;letter-spacing:1.4px;text-transform:uppercase;padding:6px 12px;border-radius:999px}
.hero h1{font-size:46px;font-weight:800;letter-spacing:-.5px;color:var(--pine);margin:16px 0 12px}
.hero p.sub{font-size:17.5px;color:var(--muted);max-width:640px;margin:0 auto;line-height:1.55}
.trust{display:flex;justify-content:center;gap:8px;flex-wrap:wrap;margin-top:18px}
.trust span{font-size:12.5px;font-weight:600;color:var(--pine);background:#fff;border:1px solid var(--line);padding:6px 12px;border-radius:999px}
.trust span b{color:var(--orange-d)}

/* calculator panel */
.calc{max-width:740px;margin:26px auto 0;background:var(--card);border:1px solid var(--line);border-radius:18px;box-shadow:0 18px 40px -22px rgba(30,43,38,.35);overflow:hidden}
.calc-head{background:var(--pine);color:#fff;padding:14px 22px;display:flex;align-items:center;gap:10px}
.calc-head .dot{width:9px;height:9px;border-radius:50%;background:var(--orange)}
.calc-head h2{font-size:16.5px;font-weight:700;letter-spacing:.2px}
.calc-head span{margin-left:auto;font-size:12px;color:#c9cfc4;font-weight:500}
.calc-body{padding:22px}
.seg{display:flex;background:var(--paper);border:1px solid var(--line);border-radius:10px;padding:3px;gap:3px}
.seg button{flex:1;border:0;background:transparent;font:inherit;font-size:13px;font-weight:600;color:var(--muted);padding:8px 4px;border-radius:8px;cursor:pointer}
.seg button.on{background:var(--pine);color:#fff}
.seg-row{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-bottom:18px}
.seg-label{font-size:11px;font-weight:700;letter-spacing:1.1px;text-transform:uppercase;color:var(--muted);margin-bottom:6px}
.grid{display:grid;grid-template-columns:1fr 1fr;gap:14px 16px}
.field label{display:block;font-size:13px;font-weight:600;color:var(--pine);margin-bottom:6px}
.field label small{color:var(--muted);font-weight:500}
.input{display:flex;align-items:center;border:1.5px solid var(--line);border-radius:10px;background:#fff;overflow:hidden}
.input:focus-within{border-color:var(--orange)}
.input input{flex:1;border:0;outline:0;font:inherit;font-size:16px;font-weight:600;padding:11px 12px;min-width:0;color:var(--ink)}
.input .unit{font-size:12.5px;font-weight:600;color:var(--muted);background:var(--paper);padding:12px 10px;border-left:1px solid var(--line2)}
.field select{width:100%;font:inherit;font-size:15px;font-weight:600;padding:11px;border:1.5px solid var(--line);border-radius:10px;background:#fff;color:var(--ink)}
.check{display:flex;align-items:center;gap:9px;border:1.5px solid var(--line);border-radius:10px;padding:11px 12px;font-size:14.5px;font-weight:600;color:var(--pine);background:#fff;height:100%}
.check .box{width:20px;height:20px;border-radius:6px;background:var(--orange);color:#fff;display:flex;align-items:center;justify-content:center;font-size:13px;flex:none}
.chips{display:flex;gap:6px;flex-wrap:wrap;margin-top:8px}
.chips span{font-size:12px;font-weight:600;border:1px solid var(--line);background:var(--paper);border-radius:999px;padding:4px 10px;color:var(--muted)}
.chips span.on{background:var(--orange-soft);border-color:var(--orange);color:var(--orange-d)}
.results{margin-top:22px;border-top:2px dashed var(--line);padding-top:18px}
.results h3{font-size:12px;letter-spacing:1.2px;text-transform:uppercase;color:var(--muted);margin-bottom:12px}
.hero-result{background:var(--orange-soft);border:1.5px solid var(--orange);border-radius:12px;padding:14px 16px;display:flex;align-items:center;gap:14px;margin-bottom:12px}
.hero-result .lbl{font-size:12px;font-weight:700;letter-spacing:1px;text-transform:uppercase;color:var(--orange-d)}
.hero-result .val{font-family:'Archivo';font-size:30px;font-weight:800;color:var(--pine);line-height:1}
.hero-result .buy{margin-left:auto;text-align:right;font-size:12.5px;color:var(--muted);font-weight:500}
.hero-result .buy b{display:block;font-size:15px;color:var(--pine)}
.tiles{display:grid;grid-template-columns:repeat(4,1fr);gap:10px}
.tile{background:var(--paper);border:1px solid var(--line2);border-radius:12px;padding:11px 12px}
.tile .t{font-size:11px;font-weight:700;letter-spacing:.8px;text-transform:uppercase;color:var(--muted)}
.tile .v{font-family:'Archivo';font-size:18.5px;font-weight:700;color:var(--pine);margin-top:3px}
.tile .v small{font-size:12px;color:var(--muted);font-weight:600}
.matrow{margin-top:12px;background:var(--steel-soft);border:1px solid #cfdfd7;border-radius:12px;padding:12px 16px;font-size:14px;color:var(--pine);display:flex;gap:8px;flex-wrap:wrap;align-items:center}
.matrow b{font-weight:700}
.matrow .sep{color:#9db4a9}
.calc-actions{display:flex;gap:10px;margin-top:16px;align-items:center}
.btn-print{font:inherit;font-size:13.5px;font-weight:600;background:var(--pine);color:#fff;border:0;border-radius:10px;padding:10px 16px;cursor:pointer}
.calc-actions span{font-size:12.5px;color:var(--muted)}
.diagram{max-width:740px;margin:14px auto 0;background:#fff;border:1px solid var(--line);border-radius:18px;padding:18px 14px 8px}
.diagram figcaption{text-align:center;font-size:12.5px;color:var(--muted);padding:8px 0 10px}

/* sections */
section{padding:40px 0 4px}
.sec-kicker{font-size:12px;font-weight:700;letter-spacing:1.4px;text-transform:uppercase;color:var(--orange-d)}
section h2{font-size:29px;font-weight:800;color:var(--pine);letter-spacing:-.3px;margin:8px 0 12px}
section p{font-size:16px;line-height:1.65;color:#3c423e;margin-bottom:12px}
section p b{color:var(--pine)}
.formula{background:var(--pine);color:#eef0e9;border-radius:14px;padding:18px 22px;font-size:17px;text-align:center;margin:16px 0}
.formula .mono{color:#ffd9ad;font-size:19px}
table{width:100%;border-collapse:collapse;background:#fff;border:1px solid var(--line);border-radius:12px;overflow:hidden;font-size:14.5px}
th{background:var(--pine);color:#fff;text-align:left;font-family:'Archivo';font-weight:600;font-size:13px;letter-spacing:.4px;padding:11px 14px}
td{padding:9px 14px;border-top:1px solid var(--line2);color:#3c423e}
tr.alt td{background:var(--amber-row)}
td.num{font-family:'IBM Plex Mono';font-size:13.5px}
.more-link{display:inline-block;margin-top:12px;font-weight:600;font-size:15px}
.cards3{display:grid;grid-template-columns:repeat(3,1fr);gap:14px;margin-top:6px}
.xcard{background:#fff;border:1px solid var(--line);border-radius:14px;padding:18px}
.xcard .tag{font-size:11px;font-weight:700;letter-spacing:1px;text-transform:uppercase;color:var(--steel)}
.xcard h3{font-size:17px;font-weight:700;color:var(--pine);margin:7px 0 8px}
.xcard p{font-size:14px;line-height:1.6;color:var(--muted);margin:0}
.xcard .res{margin-top:12px;border-top:1px dashed var(--line);padding-top:10px;font-size:14px;color:var(--pine)}
.mistakes{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-top:6px}
.mistake{background:#fff;border:1px solid var(--line);border-left:4px solid var(--orange);border-radius:10px;padding:14px 16px}
.mistake h3{font-size:15.5px;color:var(--pine);margin-bottom:5px}
.mistake p{font-size:14px;color:var(--muted);line-height:1.55;margin:0}
.toolgrid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-top:6px}
.tool{background:#fff;border:1px solid var(--line);border-radius:12px;padding:15px 16px;display:block}
.tool h3{font-size:15.5px;color:var(--pine);font-weight:700}
.tool h3::after{content:" →";color:var(--orange)}
.tool p{font-size:13px;color:var(--muted);margin:5px 0 0;line-height:1.5}
.methods{background:#fff;border:1px solid var(--line);border-radius:14px;padding:20px 22px}
.methods p{font-size:14.5px;margin-bottom:8px}
.byline{display:flex;gap:12px;align-items:center;margin-top:14px;border-top:1px dashed var(--line);padding-top:14px}
.avatar{width:42px;height:42px;border-radius:50%;background:var(--steel);color:#fff;display:flex;align-items:center;justify-content:center;font-family:'Archivo';font-weight:700;font-size:16px;flex:none}
.byline .who{font-size:14px;color:var(--pine);font-weight:600}
.byline .who small{display:block;color:var(--muted);font-weight:500;font-size:12.5px}
.faq{border-top:1px solid var(--line);margin-top:8px}
.faq details{border-bottom:1px solid var(--line);padding:14px 2px}
.faq summary{font-family:'Archivo';font-weight:600;font-size:16px;color:var(--pine);cursor:pointer;list-style:none;display:flex;justify-content:space-between;gap:10px}
.faq summary::after{content:"+";color:var(--orange);font-weight:800}
.faq details p{font-size:14.5px;color:var(--muted);margin:9px 0 2px;line-height:1.6}
footer{background:var(--pine);color:#cfd4c9;margin-top:52px}
.foot{max-width:1100px;margin:0 auto;padding:34px 20px 26px;display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:26px}
.foot h4{color:#fff;font-size:13px;letter-spacing:1.1px;text-transform:uppercase;margin-bottom:11px}
.foot a{display:block;color:#cfd4c9;font-size:14px;padding:3px 0}
.foot .fbrand{font-family:'Archivo';color:#fff;font-size:18px;font-weight:800;margin-bottom:8px}
.foot p{font-size:13.5px;line-height:1.6;color:#a9b3a5;max-width:300px}
.legal{border-top:1px solid #33443b;max-width:1100px;margin:0 auto;padding:15px 20px;font-size:12.5px;color:#8e9a8c;display:flex;justify-content:space-between;gap:14px;flex-wrap:wrap}

@media (max-width:720px){
  nav.main{display:none}.burger{display:block}
  .hero{padding:30px 0 4px}.hero h1{font-size:33px}.hero p.sub{font-size:16px}
  .seg-row{grid-template-columns:1fr}
  .grid{grid-template-columns:1fr 1fr;gap:12px}
  .tiles{grid-template-columns:1fr 1fr}
  .hero-result .val{font-size:25px}
  section h2{font-size:24px}
  .cards3{grid-template-columns:1fr}
  .mistakes{grid-template-columns:1fr}
  .toolgrid{grid-template-columns:1fr 1fr}
  .foot{grid-template-columns:1fr 1fr}
  .calc-body{padding:16px}
  th,td{padding:8px 10px;font-size:13.5px}
}
@media (max-width:430px){ .grid{grid-template-columns:1fr} .toolgrid{grid-template-columns:1fr} }

/* inner pages */
.crumbs{max-width:860px;margin:0 auto;padding:16px 20px 0;font-size:13px;color:var(--muted)}
.crumbs a{color:var(--steel);font-weight:500}
.hero-inner{text-align:center;padding:22px 0 4px}
.hero-inner h1{font-size:38px;font-weight:800;letter-spacing:-.5px;color:var(--pine);margin:12px 0 10px}
.hero-inner p.sub{font-size:16.5px;color:var(--muted);max-width:620px;margin:0 auto;line-height:1.55}
.related{max-width:860px;margin:34px auto 0;padding:0 20px}
.related h2{font-size:21px;color:var(--pine);margin-bottom:12px}
.note{background:var(--orange-soft);border:1px solid #f0d3ac;border-radius:12px;padding:13px 16px;font-size:14.5px;color:#7a4a12;line-height:1.55}
.note b{color:#5f3809}
ul.tight{margin:4px 0 12px 20px;color:#3c423e;font-size:16px;line-height:1.65}
ul.tight li{margin-bottom:6px}
.srcs{font-size:13.5px;color:var(--muted);line-height:1.6}
.srcs a{word-break:break-all}
.bigtable{overflow-x:auto}
.bigtable table{min-width:560px}
td.hl{background:var(--orange-soft);font-weight:700;color:var(--pine)}
.prose-narrow{max-width:720px}
footer{margin-top:56px}
@media (max-width:720px){ .hero-inner h1{font-size:29px} }

/* nav dropdown + mobile panel */
.nav-group{position:relative}
.nav-dropdown{display:none;position:absolute;top:calc(100% + 6px);left:0;background:#fff;border:1px solid var(--line);border-radius:12px;box-shadow:0 16px 34px -14px rgba(30,43,38,.35);padding:8px;min-width:230px;z-index:60}
.nav-dropdown a{display:block;color:var(--pine)!important;padding:8px 11px!important;border-radius:8px;font-size:14px!important}
.nav-dropdown a:hover{background:var(--paper)}
@media (min-width:721px){ .nav-group:hover .nav-dropdown,.nav-group:focus-within .nav-dropdown{display:block} }
.mobile-nav{display:none;background:var(--pine2);padding:8px 14px 14px;max-height:calc(100dvh - 62px);overflow-y:auto}
.mobile-nav.open{display:block}
.mobile-nav a{display:block;color:#e9e5d8;font-size:15px;font-weight:500;padding:9px 6px;border-top:1px solid #33443b}