:root{
  --navy:#0b2e5c; --navy-2:#123f7a; --blue:#1f6fd1; --sky:#e8f1fc; --ink:#14202e; --muted:#5b6b7f;
  --line:#dbe3ee; --bg:#f6f8fb; --card:#fff; --ok:#1e8449; --ok-bg:#e8f6ee; --bad:#c0392b; --bad-bg:#fbeaea; --warn:#b9770e;
  --r:12px; --shadow:0 1px 2px #0b2e5c0f,0 6px 24px #0b2e5c12;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font:16px/1.55 "Inter",system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;color:var(--ink);background:var(--bg)}
a{color:var(--blue);text-decoration:none}
a:hover{text-decoration:underline}
img{max-width:100%}
.wrap{max-width:1180px;margin:0 auto;padding:0 20px}

/* header */
.top{position:sticky;top:0;z-index:20;background:#ffffffeb;backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.top .wrap{display:flex;align-items:center;gap:22px;height:64px}
.brand{display:flex;align-items:center;gap:10px;font-weight:800;letter-spacing:.12em;color:var(--navy);font-size:18px}
.brand img{width:34px;height:34px;border-radius:8px}
.brand:hover{text-decoration:none}
.nav{display:flex;gap:4px;margin-inline-start:auto;align-items:center}
.nav a{color:var(--ink);padding:8px 12px;border-radius:8px;font-weight:500;font-size:15px}
.nav a:hover,.nav a.on{background:var(--sky);color:var(--navy);text-decoration:none}
.lang{display:flex;border:1px solid var(--line);border-radius:8px;overflow:hidden;margin-inline-start:8px}
.lang button{border:0;background:#fff;padding:6px 10px;font-weight:600;cursor:pointer;color:var(--muted)}
.lang button.on{background:var(--navy);color:#fff}
.burger{display:none;margin-inline-start:auto;border:1px solid var(--line);background:#fff;border-radius:8px;padding:6px 10px;font-size:18px}

/* hero */
.hero{position:relative;color:#fff;background:#0b2e5c url(hero.jpg) center/cover no-repeat;min-height:520px;display:flex;align-items:flex-end}
.hero:before{content:"";position:absolute;inset:0;background:linear-gradient(180deg,#0b2e5c10 0%,#0b2e5c55 45%,#071d3cee 100%)}
.hero .wrap{position:relative;padding-bottom:56px;padding-top:120px}
.hero h1{font-size:clamp(32px,5vw,54px);line-height:1.08;margin:0 0 14px;max-width:820px;letter-spacing:-.01em}
.hero p{font-size:clamp(17px,2vw,20px);max-width:720px;color:#dce8f8;margin:0 0 26px}
.btn{display:inline-block;background:var(--blue);color:#fff;border:0;border-radius:10px;padding:12px 20px;font-weight:600;font-size:16px;cursor:pointer}
.btn:hover{background:#185cb0;text-decoration:none}
.btn.ghost{background:#ffffff1f;border:1px solid #ffffff66}
.btn.ghost:hover{background:#ffffff33}
.btn.light{background:#fff;color:var(--navy);border:1px solid var(--line)}
.btn:disabled{opacity:.6;cursor:wait}
.row-btn{display:flex;gap:12px;flex-wrap:wrap}

/* sections */
section{padding:64px 0}
section.alt{background:#fff;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.kicker{color:var(--blue);font-weight:700;letter-spacing:.12em;text-transform:uppercase;font-size:13px;margin-bottom:6px}
h2{font-size:clamp(26px,3vw,34px);margin:0 0 12px;color:var(--navy);letter-spacing:-.01em}
h3{margin:0 0 8px;color:var(--navy)}
.lead{color:var(--muted);font-size:18px;max-width:760px;margin:0 0 30px}
.grid{display:grid;gap:20px;grid-template-columns:repeat(auto-fill,minmax(260px,1fr))}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:22px;box-shadow:var(--shadow)}
.card p{color:var(--muted);margin:0 0 12px}
.card .ico{width:44px;height:44px;border-radius:10px;background:var(--sky);display:grid;place-items:center;margin-bottom:14px;color:var(--navy)}
.card.link{transition:transform .15s, box-shadow .15s;display:block;color:inherit}
.card.link:hover{transform:translateY(-2px);text-decoration:none;box-shadow:0 2px 4px #0b2e5c14,0 14px 34px #0b2e5c1f}
.tag{display:inline-block;font-size:12px;font-weight:600;color:var(--navy);background:var(--sky);border-radius:20px;padding:2px 10px;margin:0 6px 6px 0}
.steps{counter-reset:s;display:grid;gap:18px;grid-template-columns:repeat(auto-fit,minmax(230px,1fr))}
.steps div{position:relative;padding-inline-start:52px}
.steps div:before{counter-increment:s;content:counter(s);position:absolute;inset-inline-start:0;top:0;width:36px;height:36px;border-radius:50%;background:var(--navy);color:#fff;display:grid;place-items:center;font-weight:700}
.steps p{color:var(--muted);margin:4px 0 0}
.page-head{background:linear-gradient(120deg,var(--navy),var(--navy-2));color:#fff;padding:46px 0 38px}
.page-head h1{margin:0 0 6px;font-size:clamp(28px,4vw,40px)}
.page-head p{margin:0;color:#cfe0f5;max-width:760px}
.prose{max-width:820px}
.prose p,.prose li{color:#2b3a4d}
table.codes{width:100%;border-collapse:collapse;background:#fff;border:1px solid var(--line);border-radius:var(--r);overflow:hidden}
table.codes th,table.codes td{padding:11px 14px;border-bottom:1px solid var(--line);text-align:start;vertical-align:top}
table.codes th{background:var(--sky);color:var(--navy);font-size:14px}
table.codes td:first-child{white-space:nowrap;font-weight:600;color:var(--navy)}

/* calculator */
.calc{display:grid;grid-template-columns:minmax(330px,420px) 1fr;gap:24px;align-items:start;padding:28px 0 60px}
.panel{background:#fff;border:1px solid var(--line);border-radius:var(--r);box-shadow:var(--shadow)}
.panel h3{font-size:15px;text-transform:uppercase;letter-spacing:.08em;color:var(--muted);margin:0;padding:14px 18px;border-bottom:1px solid var(--line)}
.fs{padding:14px 18px;border-bottom:1px solid var(--line)}
.fs:last-child{border-bottom:0}
.fs .t{font-weight:700;color:var(--navy);margin-bottom:10px;font-size:15px}
.f{display:grid;grid-template-columns:1fr 150px;align-items:center;gap:8px;margin-bottom:8px}
.f label{font-size:14px;color:#33465c}
.f.w2{grid-template-columns:1fr 70px 80px}
input,select{font:inherit;font-size:15px;width:100%;padding:7px 9px;border:1px solid #c9d4e2;border-radius:8px;background:#fff;color:var(--ink)}
input:focus,select:focus{outline:2px solid #1f6fd155;border-color:var(--blue)}
.chk{display:flex;gap:8px;align-items:center;font-size:14px;margin:4px 0 8px}
.chk input{width:auto}
.tabs{display:flex;padding:10px 12px 0;gap:6px;border-bottom:1px solid var(--line)}
.tabs button{flex:1;border:1px solid var(--line);border-bottom:0;background:var(--bg);padding:10px;border-radius:10px 10px 0 0;font-weight:600;cursor:pointer;color:var(--muted)}
.tabs button.on{background:#fff;color:var(--navy);box-shadow:0 -2px 0 var(--blue) inset}
.go{padding:16px 18px}
.go .btn{width:100%}
.hint{font-size:13px;color:var(--muted)}
.res-empty{padding:60px 30px;text-align:center;color:var(--muted)}
.res-empty img{width:80px;opacity:.85;border-radius:16px;margin-bottom:10px}
.verdict{display:flex;align-items:center;gap:18px;padding:18px 20px;border-radius:var(--r) var(--r) 0 0}
.verdict.ok{background:var(--ok-bg);color:var(--ok)}
.verdict.nok{background:var(--bad-bg);color:var(--bad)}
.verdict b{font-size:22px}
.verdict .u{margin-inline-start:auto;font-size:30px;font-weight:800}
.res-body{padding:18px 20px}
.res-body h4{margin:20px 0 8px;color:var(--navy)}
table.checks{width:100%;border-collapse:collapse;font-size:14px}
table.checks th{text-align:start;color:var(--muted);font-weight:600;border-bottom:1px solid var(--line);padding:8px 6px}
table.checks td{border-bottom:1px solid #edf1f6;padding:8px 6px;vertical-align:middle}
table.checks td.n{text-align:end;white-space:nowrap;font-variant-numeric:tabular-nums}
.ref{color:var(--muted);font-size:12px}
.grp{font-size:11px;font-weight:700;border-radius:4px;padding:1px 6px;background:var(--sky);color:var(--navy)}
.bar{position:relative;height:8px;background:#edf1f6;border-radius:4px;min-width:90px}
.bar i{position:absolute;inset-inline-start:0;top:0;bottom:0;border-radius:4px}
.pct{font-weight:700;min-width:48px;text-align:end}
.fig{border:1px solid var(--line);border-radius:10px;padding:8px;background:#fff;margin:6px 0}
.notes{background:#fff8e6;border:1px solid #f3dfa8;border-radius:10px;padding:10px 14px;font-size:14px;color:#6b5210}
.err{background:var(--bad-bg);color:var(--bad);border-radius:10px;padding:12px 14px;margin:12px 18px;font-size:14px}
.spin{display:inline-block;width:16px;height:16px;border:2px solid #fff8;border-top-color:#fff;border-radius:50%;animation:sp 0.8s linear infinite;vertical-align:-3px;margin-inline-end:8px}
@keyframes sp{to{transform:rotate(360deg)}}
.disclaimer{font-size:13px;color:var(--muted);border-top:1px solid var(--line);padding:12px 20px}

/* forms */
.form{max-width:620px}
.form .f2{margin-bottom:14px}
.form label{display:block;font-weight:600;margin-bottom:5px;font-size:14px}
textarea{font:inherit;width:100%;min-height:150px;padding:9px;border:1px solid #c9d4e2;border-radius:8px}
.hp{position:absolute;left:-5000px;top:0}
.okmsg{background:var(--ok-bg);color:var(--ok);padding:12px 14px;border-radius:10px}

/* footer */
footer{background:#071d3c;color:#b9c8dc;padding:40px 0 26px;font-size:14px}
footer .cols{display:grid;grid-template-columns:2fr 1fr 1fr;gap:24px}
footer a{color:#dce8f8}
footer .brand{color:#fff;margin-bottom:10px}
footer .copy{border-top:1px solid #ffffff1f;margin-top:26px;padding-top:16px;display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap}

@media (max-width:900px){
  .calc{grid-template-columns:1fr}
  footer .cols{grid-template-columns:1fr}
  .nav{display:none;position:absolute;top:64px;left:0;right:0;background:#fff;flex-direction:column;align-items:stretch;padding:10px;border-bottom:1px solid var(--line)}
  .nav.open{display:flex}
  .burger{display:block}
  .lang{margin:6px 0 0}
  .hero{min-height:440px;background-image:url(hero-sm.jpg)}
  table.checks .hide-s{display:none}
}
@media (max-width:420px){ .f{grid-template-columns:1fr 120px} .wrap{padding:0 16px} }

/* Persian (right-to-left) */
body.fa{font-family:"Vazirmatn",system-ui,Tahoma,sans-serif;line-height:1.85}
body.fa .kicker{letter-spacing:0}
body.fa .brand{letter-spacing:.12em}
body.fa h1,body.fa h2{letter-spacing:0;line-height:1.35}
body.fa input,body.fa select,body.fa textarea,body.fa button{font-family:inherit}
body.fa .hero:before{background:linear-gradient(180deg,#0b2e5c10 0%,#0b2e5c55 45%,#071d3cee 100%)}
bdi{unicode-bidi:isolate}
body.fa table.codes td:first-child,body.fa .ref,body.fa .tag{direction:ltr;unicode-bidi:isolate}
.tabs{flex-wrap:wrap}
.tabs button{flex:1 1 30%;min-width:0;font-size:14px;padding:9px 6px;line-height:1.3}