:root{--bg:#f6f7fb;--bg2:#fff;--card:#fff;--card2:#f0f2f8;--line:rgba(20,24,60,.09);--line2:rgba(20,24,60,.16);--text:#12142b;--muted:#5b6078;
  --a:#4f46e5;--a2:#14b8a6;--grad:linear-gradient(135deg,#6366f1,#14b8a6);--ok:#16a34a;--shadow:0 20px 50px -26px rgba(40,40,120,.35);color-scheme:light}
:root[data-theme=dark]{--bg:#0b0c16;--bg2:#12132a;--card:#14162b;--card2:#1c1f3a;--line:rgba(255,255,255,.08);--line2:rgba(255,255,255,.16);--text:#f1f2fa;--muted:#9a9db8;--shadow:0 20px 60px -24px rgba(0,0,0,.7);color-scheme:dark}
@media (prefers-color-scheme:dark){:root:not([data-theme=light]){--bg:#0b0c16;--bg2:#12132a;--card:#14162b;--card2:#1c1f3a;--line:rgba(255,255,255,.08);--line2:rgba(255,255,255,.16);--text:#f1f2fa;--muted:#9a9db8;--shadow:0 20px 60px -24px rgba(0,0,0,.7);color-scheme:dark}}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{font-family:ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,Inter,sans-serif;background:var(--bg);color:var(--text);line-height:1.65;-webkit-font-smoothing:antialiased;min-height:100vh;
  background-image:radial-gradient(700px 320px at 50% -80px,rgba(99,102,241,.16),transparent 70%),radial-gradient(500px 260px at 90% 0,rgba(20,184,166,.12),transparent 70%);background-repeat:no-repeat}
a{color:inherit}
button,input,select{font:inherit;color:inherit}
.wrap{max-width:1120px;margin:0 auto;padding:0 20px}.narrow{max-width:800px}.muted{color:var(--muted)}
/* nav */
.nav{position:sticky;top:0;z-index:20;background:color-mix(in srgb,var(--bg) 78%,transparent);backdrop-filter:saturate(180%) blur(14px);-webkit-backdrop-filter:saturate(180%) blur(14px);border-bottom:1px solid var(--line)}
.nav-in{display:flex;align-items:center;gap:22px;height:62px}
.logo{display:flex;align-items:center;gap:10px;text-decoration:none;font-weight:800;font-size:20px;letter-spacing:-.02em}
.logo-mark svg{width:32px;height:32px;display:block}
.logo-text b{background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.nav-links{display:flex;gap:2px;margin-left:8px;overflow-x:auto;scrollbar-width:none;flex:1}
.nav-links::-webkit-scrollbar{display:none}
.nav-links a{white-space:nowrap;text-decoration:none;color:var(--muted);font-size:14px;font-weight:600;padding:8px 11px;border-radius:10px;transition:.15s}
.nav-links a:hover,.nav-links a[aria-current]{color:var(--text);background:var(--card2)}
.icon-btn{flex:none;width:40px;height:40px;border-radius:12px;border:1px solid var(--line);background:var(--card);display:grid;place-items:center;cursor:pointer}
.icon-btn svg{width:18px;height:18px}.i-sun{display:none}
:root[data-theme=dark] .i-sun{display:block}:root[data-theme=dark] .i-moon{display:none}
@media (prefers-color-scheme:dark){:root:not([data-theme]) .i-sun{display:block}:root:not([data-theme]) .i-moon{display:none}}
/* hero + calc */
.hero{padding:44px 0 20px;text-align:center}
h1{font-size:clamp(32px,5.4vw,50px);line-height:1.08;letter-spacing:-.03em;font-weight:800;margin-bottom:12px}
.lead{font-size:clamp(16px,2vw,18px);color:var(--muted);max-width:620px;margin:0 auto 26px}
.card{background:var(--card);border:1px solid var(--line);border-radius:20px;box-shadow:var(--shadow)}
.calc{padding:22px;text-align:left}
.sec-title{font-size:15px;font-weight:700;margin:0 0 10px;letter-spacing:0}
label{display:block;font-size:13px;font-weight:600;color:var(--muted)}
input,select{width:100%;height:46px;border:1.5px solid var(--line2);background:var(--bg2);border-radius:12px;padding:0 12px;font-size:15px;outline:0;transition:.15s;margin-top:6px}
select{appearance:none;-webkit-appearance:none;background-image:linear-gradient(45deg,transparent 50%,var(--muted) 50%),linear-gradient(135deg,var(--muted) 50%,transparent 50%);background-position:calc(100% - 17px) 20px,calc(100% - 12px) 20px;background-size:5px 5px;background-repeat:no-repeat;padding-right:30px;cursor:pointer}
input:focus,select:focus{border-color:var(--a);box-shadow:0 0 0 4px rgba(99,102,241,.18)}
.rows-head,.row{display:grid;grid-template-columns:1.7fr 1fr 1fr 40px;gap:10px;align-items:center}
.rows-head.w,.row.w{grid-template-columns:1.5fr .8fr 1.2fr .8fr 40px}
.rows-head.g,.row.g{grid-template-columns:1.8fr 1fr 1fr 40px}
.rows-head{font-size:12px;font-weight:700;text-transform:uppercase;letter-spacing:.06em;color:var(--muted);margin-bottom:8px;padding:0 2px}
.row{margin-bottom:10px}.row input,.row select{margin-top:0}
.x{width:40px;height:46px;border:1px solid var(--line);background:var(--card2);border-radius:12px;font-size:22px;line-height:1;cursor:pointer;color:var(--muted);transition:.15s}
.x:hover{color:#ef4444;border-color:#ef4444}
.actions{display:flex;gap:10px;margin:6px 0 18px}
.btn{height:42px;padding:0 16px;border-radius:12px;font-weight:700;font-size:14px;cursor:pointer;border:1px solid var(--line2);background:var(--card2);transition:.15s}
.btn:hover{border-color:var(--a);color:var(--a)}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-bottom:18px}.grid3{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}
.prev{margin-bottom:6px}
.chips{display:flex;gap:8px;flex-wrap:wrap;margin:14px 0 18px}
.chip{height:34px;padding:0 12px;border-radius:999px;border:1px solid var(--line2);background:var(--card2);font-size:13px;font-weight:600;cursor:pointer;transition:.15s}.chip:hover{border-color:var(--a);color:var(--a)}
.one{margin-bottom:16px}
.seg{display:flex;gap:4px;background:var(--card2);border-radius:14px;padding:4px;margin-bottom:16px}
.seg button{flex:1;height:40px;border:0;border-radius:10px;background:transparent;font-weight:700;font-size:14px;color:var(--muted);cursor:pointer;transition:.2s}
.seg button.on{background:var(--grad);color:#fff;box-shadow:0 8px 18px -10px rgba(79,70,229,.7)}
.pc{padding:14px 0;border-bottom:1px solid var(--line)}.pc:last-child{border:0}
.inline{display:flex;align-items:center;gap:10px;flex-wrap:wrap}.inline input{width:110px;margin:0}.inline span{color:var(--muted);font-weight:600}
.inline output{font-size:24px;font-weight:800;background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}
/* result */
.result{display:flex;flex-direction:column;gap:14px;border-radius:16px;padding:20px;background:linear-gradient(135deg,rgba(99,102,241,.12),rgba(20,184,166,.12));border:1px solid var(--line);animation:in .3s ease}
@keyframes in{from{opacity:.4;transform:translateY(4px)}}
.r-big{font-size:clamp(42px,9vw,60px);font-weight:800;letter-spacing:-.03em;line-height:1;background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.r-label{font-weight:700;color:var(--muted);margin-top:4px}
.r-rows{display:grid;grid-template-columns:repeat(auto-fit,minmax(130px,1fr));gap:10px}
.r-rows div{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:10px 12px}
.r-rows dt{font-size:12px;color:var(--muted);font-weight:600}.r-rows dd{font-size:18px;font-weight:800}
.r-note{font-size:13.5px;color:var(--muted)}
/* sections */
section h2{font-size:clamp(22px,3vw,30px);letter-spacing:-.02em;line-height:1.2;margin-bottom:14px;font-weight:800}
.article{padding:44px 0 8px}
.prose h2{margin:30px 0 12px}.prose h2:first-child{margin-top:0}.prose h3{font-size:18px;margin:20px 0 6px}
.prose p{color:var(--muted);margin-bottom:14px}.prose ul,.prose ol{padding-left:22px;color:var(--muted);margin-bottom:14px}.prose li{margin-bottom:6px}
.prose strong{color:var(--text)}.prose a{color:var(--a);font-weight:600}
.formula{background:var(--card);border:1px solid var(--line);border-left:4px solid var(--a);border-radius:10px;padding:12px 16px;color:var(--text)!important;font-weight:600;overflow-x:auto}
.tbl-wrap{overflow-x:auto;margin:6px 0 16px;border:1px solid var(--line);border-radius:12px}
table{width:100%;border-collapse:collapse;font-size:14.5px;background:var(--card)}
th,td{padding:9px 14px;text-align:left;border-bottom:1px solid var(--line)}th{background:var(--card2);font-size:12.5px;text-transform:uppercase;letter-spacing:.05em;color:var(--muted)}tr:last-child td{border:0}
.faq{padding:34px 0}
details{border:1px solid var(--line);background:var(--card);border-radius:14px;margin-bottom:10px;overflow:hidden}details[open]{border-color:var(--line2)}
summary{cursor:pointer;list-style:none;padding:15px 48px 15px 18px;font-weight:700;position:relative}summary::-webkit-details-marker{display:none}
summary::after{content:"+";position:absolute;right:18px;top:50%;transform:translateY(-50%);font-size:22px;color:var(--muted);transition:.2s}details[open] summary::after{transform:translateY(-50%) rotate(45deg)}
details p{padding:0 18px 16px;color:var(--muted)}
.tools{padding:20px 0 56px}.tool-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:12px}
.tool{display:flex;flex-direction:column;gap:4px;padding:16px;border-radius:14px;background:var(--card);border:1px solid var(--line);text-decoration:none;transition:.2s}
.tool b{font-size:15px}.tool span{font-size:13.5px;color:var(--muted)}.tool:hover{border-color:var(--a);transform:translateY(-2px)}
.legal{padding:44px 0 60px}.legal .card{padding:30px}.legal h1{font-size:clamp(28px,4vw,38px);margin-bottom:14px;text-align:left}
.footer{border-top:1px solid var(--line);padding:42px 0 26px;background:var(--bg2)}
.foot-grid{display:grid;grid-template-columns:1.5fr 1fr 1fr 1fr;gap:28px}.foot-grid p{font-size:14px;margin-top:10px;max-width:290px}
.footer h3{font-size:12.5px;text-transform:uppercase;letter-spacing:.08em;color:var(--muted);margin-bottom:10px}
.footer a:not(.logo){display:block;text-decoration:none;font-size:14px;padding:4px 0;opacity:.85}.footer a:not(.logo):hover{color:var(--a);opacity:1}
.copy{margin-top:26px;padding-top:18px;border-top:1px solid var(--line);font-size:13px;color:var(--muted)}
@media (max-width:760px){
  .nav-in{gap:10px}.logo-text{font-size:18px}
  .hero{padding:30px 0 14px}.calc{padding:14px}
  .grid2,.grid3{grid-template-columns:1fr}
  .rows-head{display:none}
  .row,.row.w,.row.g{grid-template-columns:1fr 1fr;gap:8px;padding:12px;border:1px solid var(--line);border-radius:14px;background:var(--bg2)}
  .row .c-name,.row .g-n{grid-column:1/-1}
  .row .x{grid-column:1/-1;width:100%;height:36px;font-size:16px}
  .row .x::after{content:" Remove";font-size:13px;font-weight:600}
  .foot-grid{grid-template-columns:1fr 1fr}
  .inline input{width:90px}
}
@media (prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}}