:root{--ink:#10264d;--muted:#5e6f88;--line:#e0e9f0;--bg:#f6f9fc;--brand:#0099a8;--brand-ink:#007f8d;--soft:#eaf8fa;font-family:Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;color:var(--ink);background:var(--bg)}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);line-height:1.5}
a{color:inherit;text-decoration:none}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
[hidden]{display:none!important}
.wrap{max-width:1180px;margin:auto;padding:0 24px}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
.skip{position:absolute;left:-9999px}.skip:focus{left:16px;top:16px;background:#fff;padding:8px 12px;border-radius:8px;z-index:10}

/* header */
.nav{background:#fff;border-bottom:1px solid #e3ebf2;position:relative;z-index:5}
.nav .wrap{display:flex;align-items:center;justify-content:space-between;min-height:58px;gap:20px}
.logo{font-size:22px;font-weight:850;letter-spacing:-1px;white-space:nowrap}
.logo span{color:#00a3ba}
.links{display:flex;gap:24px;font-size:14px;font-weight:650}
.links a:hover{color:var(--brand-ink)}
.nav-right{display:flex;align-items:center;gap:6px}
.lang{position:relative}
.lang summary{list-style:none;cursor:pointer;padding:7px 10px;border-radius:10px;color:var(--muted);font-size:14px;font-weight:600;white-space:nowrap}
.lang summary::-webkit-details-marker{display:none}
.lang summary:hover,.lang[open] summary{background:#f1f6fa}
.lang 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:12px;box-shadow:0 12px 32px #10264d1a;min-width:170px}
.lang li a{display:block;padding:9px 12px;border-radius:8px;font-size:14px}
.lang li a:hover{background:#f1f6fa}
.lang li a[aria-current]{color:var(--brand-ink);font-weight:700}
.menu-btn{display:none;background:none;border:0;padding:6px 8px;border-radius:10px;font-size:22px;line-height:1}

/* hero + search */
.hero{padding:20px 0 18px;background:radial-gradient(circle at 85% 35%,#d7f4fb,transparent 36%),#fff;border-bottom:1px solid #e8eff4}
.hero h1{font-size:clamp(27px,3.4vw,38px);letter-spacing:-1.6px;line-height:1.1;margin:0 0 8px}
.hero h1 em{font-style:normal;color:#009eac}
.hero p{font-size:16px;color:var(--muted);margin:0}
.search{display:flex;background:#fff;border:1px solid #dce6ed;box-shadow:0 10px 26px #10264d10;border-radius:14px;padding:5px;max-width:640px;margin:16px 0 0}
.search input{border:0;outline:0;flex:1;min-width:0;padding:10px 12px;font-size:16px;background:transparent}
.btn{background:var(--brand);color:#fff;border:0;border-radius:10px;padding:10px 20px;font-weight:700}
.btn:hover{background:var(--brand-ink)}

/* headings + generic cards (category pages) */
.section{padding-top:20px;padding-bottom:20px}
.heading{display:flex;align-items:baseline;justify-content:space-between;gap:15px;margin-bottom:12px}
.heading h2{font-size:20px;letter-spacing:-.5px;margin:0}
.heading small{color:#6d7b91}
.grid{display:grid;grid-template-columns:repeat(4,1fr);gap:10px}
.card{display:flex;gap:10px;align-items:flex-start;background:#fff;border:1px solid var(--line);border-radius:12px;padding:10px 14px;transition:border-color .2s,box-shadow .2s}
.card:hover{border-color:#06a7b4;box-shadow:0 6px 16px #10264d0c}
.icon{font-size:19px;line-height:1.3;text-align:center;flex:0 0 28px}
.txt{min-width:0}
.card strong{display:block;font-size:14px;line-height:1.35}
.card small{display:-webkit-box;-webkit-line-clamp:1;-webkit-box-orient:vertical;overflow:hidden;color:#738096;margin-top:2px;font-size:12.5px;line-height:1.4}
.empty{padding:20px 0;color:#65758a}
.grid.cats{grid-template-columns:repeat(6,1fr)}
.card.cat{flex-direction:column;gap:4px;padding:10px 12px}
.card.cat .icon{flex:none;text-align:left}
.swap-btn{display:inline-flex;align-items:center;gap:6px;margin-top:12px;padding:8px 14px;border:1px solid var(--brand);border-radius:10px;color:var(--brand-ink);font-weight:700;font-size:14px;background:#fff}
.swap-btn:hover{background:var(--soft)}

/* home directory */
.dir{padding-top:14px;padding-bottom:6px}
.dir .heading{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}
.dir-grid{display:grid;grid-template-columns:repeat(6,1fr);gap:10px;align-items:start}
.dcat{background:#fff;border:1px solid var(--line);border-radius:14px;padding:10px 10px 8px}
.dcat summary{list-style:none;display:flex;align-items:center;gap:6px;font-weight:750;font-size:14px;padding:2px 4px 8px;border-bottom:1px solid #edf2f6;margin-bottom:4px;pointer-events:none}
.dcat summary::-webkit-details-marker{display:none}
.dname{flex:1;min-width:0}
.dn{font-size:11.5px;font-weight:700;color:var(--brand-ink);background:var(--soft);border-radius:20px;padding:1px 7px}
.dcat ul{list-style:none;margin:0;padding:0}
.dcat li a{display:flex;gap:6px;align-items:baseline;padding:3px 4px;border-radius:7px;font-size:13.5px;line-height:1.35}
.dcat li a:hover{background:#f1f6fa;color:var(--brand-ink)}
.di{flex:0 0 18px;text-align:center;font-size:13px}

/* tool page */
.page{padding-top:16px;padding-bottom:6px}
.crumb{color:var(--muted);font-size:12.5px;margin-bottom:6px}
.crumb a:hover{color:var(--brand-ink);text-decoration:underline}
.tooltitle{font-size:clamp(24px,3vw,32px);letter-spacing:-1px;margin:0 0 2px;line-height:1.15}
.lead{color:var(--muted);margin:0 0 14px;font-size:15px}
.panel{background:#fff;border:1px solid #dce7ef;border-radius:16px;padding:18px 20px;box-shadow:0 8px 30px #10264d08}
.panel h2{margin:0 0 6px;font-size:18px;letter-spacing:-.3px}
.panel h3{font-size:14px;margin:14px 0 6px}
.panel p{line-height:1.65;margin:0 0 10px}
.calc-grid{display:grid;grid-template-columns:minmax(0,1.55fr) minmax(0,1fr);gap:14px;align-items:start}
.fields{display:grid;grid-template-columns:repeat(auto-fill,minmax(190px,1fr));gap:10px 14px}
.field{display:grid;grid-template-rows:1fr auto;gap:5px;margin:0}
.field.full{grid-column:1/-1}
.field label{font-weight:650;font-size:13px;line-height:1.3;align-self:end}
.field input,.field select,.field textarea{width:100%;padding:8px 11px;border:1px solid #d3e0e9;border-radius:9px;background:#fff;font-size:16px;height:42px}
.field textarea{height:auto;min-height:64px;resize:vertical}
.field input:focus,.field select:focus,.field textarea:focus{border-color:var(--brand);outline:3px solid #48c9d633}
.hint{font-size:13px;color:var(--muted);background:#f1f6fa;padding:8px 11px;border-radius:9px;margin:0 0 10px}
.result{background:var(--soft);border:1px solid #cdeef2;border-radius:16px;padding:16px 20px;display:flex;flex-direction:column;justify-content:center}
.result>small{font-weight:650;color:var(--brand-ink);text-transform:uppercase;letter-spacing:.06em;font-size:11.5px}
.out-main{display:block;font-size:32px;font-weight:800;letter-spacing:-1px;line-height:1.2;margin:2px 0 0;overflow-wrap:anywhere}
.out-main-label{color:var(--muted);font-size:13.5px}
.out-list{margin:10px 0 0;padding:10px 0 0;border-top:1px solid #cdeef2;display:grid;gap:4px}
.out-list div{display:flex;justify-content:space-between;gap:14px;font-size:14px}
.out-list dt{color:var(--muted)}
.out-list dd{margin:0;font-weight:700;text-align:right;overflow-wrap:anywhere}
.err{color:#b4233c;font-weight:600;font-size:14px;margin-top:6px}
.info-grid{display:grid;grid-template-columns:minmax(0,1.55fr) minmax(0,1fr);gap:14px;margin-top:14px;align-items:start}
.info p{font-size:14.5px}
.formula{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:13px;background:#f1f6fa;border-radius:9px;padding:10px 12px;white-space:pre-wrap;overflow-x:auto;margin:0 0 10px}
.notice{background:#f1f6fa;padding:10px 12px;border-radius:10px;font-size:12.5px!important;color:#54657d;line-height:1.5!important;margin:0!important}
.example{font-size:13px!important;color:var(--muted)}
.rel ul{list-style:none;margin:0;padding:0}
.rel li a{display:flex;gap:8px;align-items:baseline;padding:6px 6px;border-radius:8px;font-size:14px}
.rel li a:hover{background:#f1f6fa;color:var(--brand-ink)}

/* prose pages */
.prose{max-width:760px}
.prose h2{font-size:20px;margin:24px 0 6px}
.prose p{line-height:1.75;color:#2a3d5e}
.prose a{color:var(--brand-ink);text-decoration:underline}

/* footer */
.footer{margin-top:28px;padding:20px 0;border-top:1px solid #dde7ef;color:#68788c;font-size:13px;background:#fff}
.footer .wrap{display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap}
.footer nav{display:flex;gap:18px;flex-wrap:wrap}
.footer a:hover{color:var(--brand-ink);text-decoration:underline}

button:focus-visible,a:focus-visible,input:focus-visible,summary:focus-visible,select:focus-visible{outline:3px solid #48c9d6;outline-offset:2px}

@media(max-width:1100px){
  .dir-grid{grid-template-columns:repeat(3,1fr)}
  .grid.cats{grid-template-columns:repeat(3,1fr)}
}
@media(max-width:900px){
  .grid{grid-template-columns:repeat(3,1fr)}
  .calc-grid,.info-grid{grid-template-columns:1fr}
}
@media(max-width:800px){
  .grid{grid-template-columns:repeat(2,1fr)}
  .menu-btn{display:block}
  .links{display:none;position:absolute;left:0;right:0;top:100%;background:#fff;border-bottom:1px solid #e3ebf2;flex-direction:column;gap:0;padding:8px 16px 14px;box-shadow:0 12px 24px #10264d14}
  .links a{padding:12px 8px;border-radius:8px;font-size:16px}
  .nav-open .links{display:flex}
  /* home: collapsible categories */
  .dir-grid{grid-template-columns:1fr;gap:8px}
  .dcat{padding:0;border-radius:12px}
  .dcat summary{pointer-events:auto;cursor:pointer;padding:12px 14px;margin:0;border:0;font-size:15px}
  .dcat summary::after{content:"›";font-size:20px;line-height:1;color:var(--muted);transition:transform .2s;margin-left:4px}
  .dcat[open] summary::after{transform:rotate(90deg)}
  .dcat[open] summary{border-bottom:1px solid #edf2f6}
  .dcat ul{padding:4px 8px 8px}
  .dcat li a{padding:8px 6px;font-size:15px}
}
@media(max-width:520px){
  .wrap{padding:0 16px}
  .nav .wrap{min-height:52px}
  .logo{font-size:20px}
  .hero{padding:18px 0 16px}
  .hero h1{font-size:27px;letter-spacing:-1px}
  .hero p{font-size:14.5px}
  .search{margin-top:12px}
  .btn{padding:10px 14px}
  .grid{gap:8px}
  .card{padding:9px 10px;gap:8px}
  .icon{font-size:17px;flex-basis:22px}
  .card strong{font-size:13.5px}
  .card small{display:none}
  #categories .heading small{display:none}
  .section{padding-top:14px;padding-bottom:10px}
  .heading{margin-bottom:8px}
  .heading h2{font-size:18px}
  .page{padding-top:10px}
  .crumb{display:none}
  .tooltitle{font-size:23px}
  .lead{font-size:13.5px;margin-bottom:10px;display:-webkit-box;-webkit-line-clamp:1;-webkit-box-orient:vertical;overflow:hidden}
  .panel{padding:14px;border-radius:14px}
  .calc-grid{gap:10px}
  .fields{grid-template-columns:1fr 1fr;gap:8px 10px}
  .field label{font-size:12.5px}
  .field input,.field select{height:40px;padding:7px 9px}
  .field select{font-size:15px}
  .result{padding:12px 14px;border-radius:14px}
  .out-main{font-size:26px}
  .out-list div{font-size:13.5px}
}