:root{
  --ink:#15233b;          /* dark navy text */
  --muted:#5d6b81;
  --line:#e6eaf1;
  --bg:#ffffff;
  --page-bg:#e7f0fb;      /* soft blue page background */
  --page-bg2:#dbe9fa;
  --bg-soft:#eef4fd;      /* light airy panel */
  --accent:#2563eb;       /* mainstream trustworthy blue */
  --accent-d:#1d4ed8;
  --accent-soft:#e8f0fe;
  --good:#15925c;
  --radius:12px;
  --wrap:1080px;
  --font:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  --mono:"SFMono-Regular",Consolas,"Liberation Mono",Menlo,monospace;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font-family:var(--font);color:var(--ink);
  background:linear-gradient(180deg,var(--page-bg) 0%,var(--page-bg2) 100%);
  background-attachment:fixed;
  line-height:1.6;font-size:16px;-webkit-font-smoothing:antialiased}
a{color:var(--accent-d);text-decoration:none}
a:hover{text-decoration:underline}
img,svg{max-width:100%}
main{max-width:var(--wrap);margin:0 auto;padding:0 20px 72px}
h1,h2,h3{line-height:1.25;color:var(--ink)}

/* header */
.site-head{position:sticky;top:0;z-index:20;background:rgba(255,255,255,.92);
  backdrop-filter:saturate(1.4) blur(8px);border-bottom:1px solid var(--line)}
.head-in{max-width:var(--wrap);margin:0 auto;display:flex;align-items:center;gap:20px;
  padding:12px 20px;flex-wrap:wrap}
.brand{font-weight:800;font-size:1.3rem;letter-spacing:-.02em;color:var(--ink)}
.brand:hover{text-decoration:none}
.brand b{color:var(--accent)}
.nav{display:flex;gap:14px;flex-wrap:wrap;font-size:.9rem}
.nav a{color:var(--muted)}
.nav a:hover{color:var(--ink);text-decoration:none}
.lang-dd{margin-left:auto;position:relative;font-size:.85rem}
.lang-dd details{position:relative}
.lang-dd summary{list-style:none;cursor:pointer;display:flex;align-items:center;gap:8px;
  padding:6px 12px;border:1px solid var(--line);border-radius:8px;background:#fff;
  font-weight:600;color:var(--ink);user-select:none}
.lang-dd summary::-webkit-details-marker{display:none}
.lang-dd summary .flag{font-size:1.05rem;line-height:1}
.lang-dd summary .chev{margin-left:2px;color:var(--muted);transition:transform .15s}
.lang-dd details[open] summary .chev{transform:rotate(180deg)}
.lang-dd ul{position:absolute;right:0;top:calc(100% + 6px);margin:0;padding:6px;
  list-style:none;background:#fff;border:1px solid var(--line);border-radius:10px;
  box-shadow:0 10px 30px rgba(21,35,59,.14);min-width:120px;z-index:40}
.lang-dd li{margin:0}
.lang-dd li a{display:flex;align-items:center;justify-content:space-between;gap:14px;
  padding:9px 12px;border-radius:7px;color:var(--ink)}
.lang-dd li a:hover{background:var(--accent-soft);text-decoration:none}
.lang-dd li a .flag{font-size:1.15rem;line-height:1}
.lang-dd li a .abbr{color:var(--muted);font-weight:600;font-size:.8rem;letter-spacing:.04em}
.lang-dd li a[aria-current] .abbr{color:var(--accent-d)}

/* breadcrumb */
.crumb{font-size:.82rem;color:var(--muted);margin:18px 0 6px}
.crumb a{color:var(--muted)}

/* hero */
.hero{display:grid;grid-template-columns:1.4fr .9fr;gap:28px;align-items:center;
  padding:26px 0 8px}
.hero-art{width:100%;height:auto;background:var(--bg-soft);border:1px solid var(--line);
  border-radius:var(--radius);padding:18px}
.hero h1{font-size:2.15rem;letter-spacing:-.025em;margin:.1rem 0 .4rem}
.hero p{color:var(--muted);margin:0;max-width:52ch}
@media(max-width:760px){.hero{grid-template-columns:1fr}.hero-art{order:-1;max-width:280px}}

/* home hero */
.home-hero{text-align:center;padding:64px 0 40px}
.home-hero h1{font-size:3.2rem;letter-spacing:-.03em;margin:0}
.home-hero .tag{font-size:1.35rem;color:var(--accent-d);font-weight:600;margin:.4rem 0 0}
.home-hero .sub{color:var(--muted);max-width:46ch;margin:.8rem auto 0}
.searchbar{max-width:520px;margin:26px auto 0}
.searchbar input{width:100%;padding:14px 18px;border:1px solid var(--line);border-radius:30px;
  font-size:1rem;font-family:var(--font);box-shadow:0 2px 10px rgba(21,35,59,.05)}
.searchbar input:focus{outline:2px solid var(--accent);border-color:var(--accent)}

/* category grid */
.cat-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(210px,1fr));gap:16px;
  margin-top:34px}
.cat-card{display:flex;flex-direction:column;gap:10px;border:1px solid var(--line);
  border-radius:var(--radius);padding:18px;background:var(--bg);transition:.15s}
.cat-card:hover{border-color:var(--accent);box-shadow:0 6px 20px rgba(37,99,235,.08);
  transform:translateY(-2px);text-decoration:none}
.cat-card .ico{width:56px;height:42px}
.cat-card h3{margin:0;font-size:1.05rem}
.cat-card small{color:var(--muted)}

/* calculator list */
.calc-list{list-style:none;padding:0;margin:22px 0;display:grid;
  grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:10px}
.calc-list a{display:block;padding:13px 15px;border:1px solid var(--line);border-radius:10px;
  background:var(--bg);color:var(--ink)}
.calc-list a:hover{border-color:var(--accent);background:var(--bg-soft);text-decoration:none}

/* calculator page */
.calc-wrap{display:grid;grid-template-columns:1fr .95fr;gap:26px;margin:22px 0 8px;align-items:start}
@media(max-width:820px){.calc-wrap{grid-template-columns:1fr}}
.panel{background:var(--bg);border:1px solid var(--line);border-radius:var(--radius);padding:22px}
.calc-form{display:grid;gap:15px}
.calc-form label{display:grid;gap:6px;font-size:.85rem;color:var(--muted);font-weight:500}
.inp{position:relative;display:flex;align-items:center}
.inp .pre{position:absolute;left:12px;color:var(--muted);font-size:.95rem}
.calc-form input{width:100%;font-family:var(--mono);font-size:1rem;padding:11px 12px;
  border:1px solid var(--line);border-radius:9px;color:var(--ink);background:#fff}
.inp.has-pre input{padding-left:26px}
.calc-form input:focus{outline:2px solid var(--accent);border-color:var(--accent)}
.btn-row{display:flex;gap:10px;margin-top:2px}
.btn{flex:1;padding:12px;border:0;border-radius:9px;font-weight:600;cursor:pointer;font-size:.95rem}
.btn-go{background:var(--accent);color:#fff}
.btn-go:hover{background:var(--accent-d)}
.btn-clear{background:var(--bg-soft);color:var(--muted);border:1px solid var(--line)}

.result-card{background:linear-gradient(160deg,#1d4ed8,#2563eb);color:#fff;border:0}
.result-card .lbl{font-size:.78rem;letter-spacing:.08em;text-transform:uppercase;color:#cfe0ff}
.result-card .big{font-family:var(--mono);font-size:2.6rem;font-weight:700;margin:4px 0 14px}
.result-breakdown{display:grid;grid-template-columns:1fr 1fr;gap:12px;border-top:1px solid rgba(255,255,255,.2);padding-top:14px}
.result-breakdown div span{display:block;font-size:.72rem;color:#cfe0ff;text-transform:uppercase;letter-spacing:.05em}
.result-breakdown div b{font-family:var(--mono);font-size:1.1rem;font-weight:600}
.chart-box{margin-top:16px}
.chart-box svg{width:100%;height:auto;background:#fff;border:1px solid var(--line);border-radius:10px}

/* schedule table */
.sched{margin-top:20px;overflow-x:auto}
.sched table{width:100%;border-collapse:collapse;font-size:.86rem}
.sched th,.sched td{padding:8px 10px;text-align:right;border-bottom:1px solid var(--line);font-variant-numeric:tabular-nums}
.sched th:first-child,.sched td:first-child{text-align:left}
.sched thead th{background:var(--bg-soft);color:var(--muted);font-weight:600;position:sticky;top:0}

/* content sections */
.content{max-width:760px;margin:44px 0}
.content section{margin:0 0 34px}
.content h2{font-size:1.35rem;margin:0 0 12px}
.content p{margin:0 0 12px}
.formula{font-family:var(--mono);background:var(--bg-soft);border:1px solid var(--line);
  border-left:3px solid var(--accent);padding:14px 16px;border-radius:8px;overflow-x:auto}
.example{background:var(--accent-soft);border-radius:10px;padding:16px 18px}
.tips{list-style:none;padding:0;display:grid;gap:10px}
.tips li{padding-left:26px;position:relative}
.tips li::before{content:"✓";position:absolute;left:0;color:var(--good);font-weight:700}
.glossary dt{font-weight:700;margin-top:12px}
.glossary dd{margin:2px 0 0;color:var(--muted)}

/* FAQ accordion */
.faq details{border:1px solid var(--line);border-radius:10px;margin-bottom:10px;
  padding:0 16px;background:var(--bg)}
.faq summary{cursor:pointer;padding:14px 0;font-weight:600;list-style:none;
  display:flex;justify-content:space-between;align-items:center}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";color:var(--accent);font-size:1.4rem;font-weight:400}
.faq details[open] summary::after{content:"–"}
.faq details[open] summary{border-bottom:1px solid var(--line)}
.faq p{color:var(--muted);padding:12px 0}

/* related */
.related ul{list-style:none;padding:0;display:grid;
  grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:10px}
.related a{display:block;padding:12px 14px;border:1px solid var(--line);border-radius:9px;background:var(--bg-soft)}
.related a:hover{border-color:var(--accent);text-decoration:none}

/* footer */
.site-foot{background:var(--bg-soft);border-top:1px solid var(--line);margin-top:40px}
.foot-in{max-width:var(--wrap);margin:0 auto;padding:40px 20px 28px;
  display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:26px}
@media(max-width:760px){.foot-in{grid-template-columns:1fr 1fr}}
.foot-in h4{font-size:.8rem;text-transform:uppercase;letter-spacing:.06em;color:var(--muted);margin:0 0 12px}
.foot-in ul{list-style:none;padding:0;margin:0;display:grid;gap:8px;font-size:.9rem}
.foot-in a{color:var(--ink)}
.foot-brand b{color:var(--accent)}
.foot-bottom{max-width:var(--wrap);margin:0 auto;padding:0 20px 28px;color:var(--muted);font-size:.8rem}
.foot-bottom .disc{border-top:1px solid var(--line);padding-top:16px;max-width:760px}

/* service page prose */
.doc{max-width:760px;margin:26px 0}
.doc h1{font-size:2rem;letter-spacing:-.02em}
.doc h2{font-size:1.25rem;margin-top:28px}
.doc p,.doc li{color:var(--ink)}

@media(prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto}}
:focus-visible{outline:2px solid var(--accent);outline-offset:2px}