:root{
  --bg:#f7f8f6; --surface:#ffffff; --ink:#15201c; --muted:#5a6a63; --line:#dfe5e1;
  --brand:#0f7a5c; --brand-ink:#ffffff; --brand-soft:#e3f3ec; --accent:#c8641c;
  --warn-bg:#fff4e5; --warn-ink:#7a4300;
  --c1:#e0a43a; --c2:#cf7a3a; --c3:#a8806c; --c4:#6d7fa8; --c5:#0f7a5c;
  --radius:14px; --shadow:0 1px 2px rgba(20,40,30,.06),0 6px 24px rgba(20,40,30,.06);
}
@media (prefers-color-scheme:dark){
  :root{ --bg:#101614; --surface:#18211e; --ink:#e8efeb; --muted:#9db0a7; --line:#2a3732;
    --brand:#3cc79b; --brand-ink:#06251b; --brand-soft:#173128; --accent:#f0a05c;
    --warn-bg:#2f2412; --warn-ink:#f1cf9a; --shadow:none; }
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font:17px/1.65 system-ui,-apple-system,"Segoe UI",Roboto,Helvetica,Arial,sans-serif}
a{color:var(--brand)} a:hover{text-decoration-thickness:2px}
img,svg{max-width:100%}
.wrap{max-width:1040px;margin:0 auto;padding:0 18px}
.skip{position:absolute;left:-999px;top:0;background:var(--brand);color:var(--brand-ink);padding:8px 14px;z-index:99}
.skip:focus{left:8px;top:8px}

/* header */
.site-header{background:var(--surface);border-bottom:1px solid var(--line);position:sticky;top:0;z-index:20}
.site-header .wrap{display:flex;align-items:center;justify-content:space-between;gap:16px;min-height:60px;flex-wrap:wrap;padding-top:6px;padding-bottom:6px}
.logo{font-weight:800;font-size:1.2rem;letter-spacing:-.02em;color:var(--ink);text-decoration:none;display:flex;align-items:center;gap:8px}
.logo .mark{display:inline-grid;place-items:center;width:28px;height:28px;border-radius:8px;background:var(--brand);color:var(--brand-ink);font-size:.95rem}
.nav{display:flex;gap:4px;flex-wrap:wrap}
.nav a{color:var(--ink);text-decoration:none;padding:8px 12px;border-radius:10px;font-size:.95rem}
.nav a:hover,.nav a[aria-current="page"]{background:var(--brand-soft);color:var(--brand)}

/* typography */
main{padding:28px 0 56px}
h1{font-size:clamp(1.8rem,4.6vw,2.6rem);line-height:1.15;letter-spacing:-.025em;margin:.2em 0 .4em}
h2{font-size:1.5rem;line-height:1.25;letter-spacing:-.015em;margin:1.8em 0 .5em}
h3{font-size:1.15rem;margin:1.5em 0 .4em}
p{margin:.7em 0}
.lede{font-size:1.18rem;color:var(--muted);max-width:62ch}
.crumbs{font-size:.88rem;color:var(--muted)}
.crumbs a{color:var(--muted)}
.meta{font-size:.88rem;color:var(--muted);margin:.4em 0 1.2em}
.article{max-width:74ch}
.article ul,.article ol{padding-left:1.3em}
.article li{margin:.35em 0}
code{background:var(--brand-soft);padding:.1em .35em;border-radius:6px;font-size:.92em}
.formula{background:var(--brand-soft);border-left:4px solid var(--brand);padding:12px 16px;border-radius:0 10px 10px 0;margin:1em 0;overflow-x:auto}

/* calculator layout */
.calc{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1.05fr);gap:22px;align-items:start;margin:22px 0}
@media (max-width:860px){.calc{grid-template-columns:1fr}}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:20px}
.card h2{margin:0 0 .6em;font-size:1.2rem}
fieldset{border:0;margin:0 0 14px;padding:0}
legend{font-weight:700;font-size:.82rem;text-transform:uppercase;letter-spacing:.06em;color:var(--muted);padding:0;margin-bottom:8px}
.field{margin:0 0 12px}
label{display:block;font-weight:600;font-size:.95rem;margin-bottom:4px}
.hint{display:block;font-weight:400;font-size:.82rem;color:var(--muted);margin-top:2px}
input[type=number],select{width:100%;padding:11px 12px;border:1px solid var(--line);border-radius:10px;background:var(--bg);color:var(--ink);font:inherit;min-height:44px}
input:focus,select:focus,button:focus-visible,a:focus-visible{outline:3px solid var(--brand);outline-offset:2px}
.row2{display:grid;grid-template-columns:1fr 1fr;gap:12px}
@media (max-width:420px){.row2{grid-template-columns:1fr}}
.actions{display:flex;gap:10px;flex-wrap:wrap}
button,.btn{font:inherit;font-weight:700;border-radius:10px;padding:11px 18px;border:1px solid var(--brand);background:var(--brand);color:var(--brand-ink);cursor:pointer;text-decoration:none;display:inline-block;min-height:44px}
button.ghost{background:transparent;color:var(--brand)}
.results{position:sticky;top:76px}
@media (max-width:860px){.results{position:static}}
.headline{background:var(--brand-soft);border-radius:12px;padding:16px 18px;margin-bottom:14px}
.kicker{display:block;font-size:.8rem;text-transform:uppercase;letter-spacing:.07em;color:var(--muted);font-weight:700}
.big{display:block;font-size:clamp(2.2rem,7vw,3rem);font-weight:800;letter-spacing:-.03em;color:var(--brand);line-height:1.1}
.sub{display:block;color:var(--muted);font-size:.92rem;margin-top:2px}
.bar{display:flex;height:16px;border-radius:99px;overflow:hidden;background:var(--line);margin:6px 0 8px}
.seg.c1,.dot.c1{background:var(--c1)} .seg.c2,.dot.c2{background:var(--c2)} .seg.c3,.dot.c3{background:var(--c3)}
.seg.c4,.dot.c4{background:var(--c4)} .seg.c5,.dot.c5{background:var(--c5)}
.legend{list-style:none;display:flex;flex-wrap:wrap;gap:4px 14px;padding:0;margin:0 0 12px;font-size:.84rem;color:var(--muted)}
.dot{display:inline-block;width:10px;height:10px;border-radius:50%;margin-right:5px}
table.res{width:100%;border-collapse:collapse;font-size:.95rem;margin:6px 0 14px}
table.res th{font-weight:400;text-align:left;padding:7px 4px;border-bottom:1px solid var(--line)}
table.res td{text-align:right;padding:7px 4px;border-bottom:1px solid var(--line);font-variant-numeric:tabular-nums;white-space:nowrap}
table.res tr.sub-total th,table.res tr.sub-total td{font-weight:700}
table.res tr.total th,table.res tr.total td{font-weight:800;border-top:2px solid var(--ink);color:var(--brand)}
.note{font-size:.86rem;color:var(--muted)}
.warn{background:var(--warn-bg);color:var(--warn-ink);padding:10px 14px;border-radius:10px;font-size:.9rem}
.callout{background:var(--warn-bg);color:var(--warn-ink);border-radius:12px;padding:14px 18px;margin:20px 0;font-size:.95rem}
.callout strong{display:block;margin-bottom:2px}

/* cards grid on home */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:16px;margin:18px 0}
.tile{display:block;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:18px;text-decoration:none;color:var(--ink);box-shadow:var(--shadow);transition:transform .15s,border-color .15s}
.tile:hover{transform:translateY(-2px);border-color:var(--brand)}
.tile h3{margin:.1em 0 .3em}
.tile p{margin:0;color:var(--muted);font-size:.93rem}
.tag{display:inline-block;font-size:.72rem;font-weight:800;text-transform:uppercase;letter-spacing:.07em;color:var(--brand);background:var(--brand-soft);padding:3px 9px;border-radius:99px}
.hero{padding:18px 0 6px}

/* FAQ */
details{background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:12px 16px;margin:10px 0}
summary{cursor:pointer;font-weight:700}
details p{margin:.6em 0 .2em}

/* ads */
.ad-slot{margin:26px auto;text-align:center;min-height:0}
.ad-slot.loaded{min-height:100px}
.ad-label{display:block;font-size:.7rem;text-transform:uppercase;letter-spacing:.08em;color:var(--muted);margin-bottom:4px}
.ad-slot ins{display:block}

/* footer */
.site-footer{border-top:1px solid var(--line);background:var(--surface);padding:30px 0;font-size:.92rem;color:var(--muted)}
.site-footer .cols{display:flex;gap:28px 48px;flex-wrap:wrap;justify-content:space-between}
.site-footer a{color:var(--muted)}
.site-footer ul{list-style:none;margin:0;padding:0}
.site-footer li{margin:6px 0}
.site-footer h4{margin:0 0 6px;color:var(--ink);font-size:.95rem}
.fine{margin-top:20px;font-size:.82rem}
@media (prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}
@media print{.site-header,.site-footer,.ad-slot,.actions{display:none}}