:root{
    --bg:#f7f4e9; --card:#ffffff; --accent:#c4451a; --accent2:#1d7a4c;
    --text:#2a2a28; --muted:#6b6a63; --border:#e3ddc9; --headbar:#2a2420;
  }
  *{box-sizing:border-box;}
  html{font-size:18px;}
  body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;background:var(--bg);color:var(--text);line-height:1.7;}
  header{padding:0 0 24px;text-align:center;background:var(--headbar);}
  header .topbar{padding:20px;border-bottom:3px solid var(--accent);}
  header h1{margin:0 0 10px;font-size:1.8rem;letter-spacing:-0.5px;color:#fff;font-weight:800;}
  header h1 span{color:var(--accent);}
  header p{margin:0;color:#cfcabd;font-size:1.05rem;padding:0 20px;}
  nav{display:flex;justify-content:center;gap:0;margin-top:0;flex-wrap:wrap;background:#fff;border-bottom:1px solid var(--border);}
  nav a{color:var(--text);text-decoration:none;font-size:1rem;font-weight:600;padding:16px 20px;border-bottom:3px solid transparent;}
  nav a:hover{color:var(--accent);border-bottom-color:var(--accent);}
  .breadcrumb{display:flex;align-items:center;gap:8px;margin:0;padding:12px 20px;background:#fff;border-bottom:1px solid var(--border);font-size:0.95rem;flex-wrap:wrap;}
  .breadcrumb a{color:var(--accent);text-decoration:none;font-weight:500;}
  .breadcrumb a:hover{text-decoration:underline;}
  .breadcrumb span{color:var(--muted);}
  .h2flag{margin-right:8px;}
  main{max-width:760px;margin:0 auto;padding:36px 20px 70px;}
  section{margin-bottom:48px;}
  h2{font-size:1.4rem;margin-bottom:8px;letter-spacing:-0.2px;font-weight:800;}
  .sub{color:var(--muted);font-size:0.98rem;margin-bottom:20px;line-height:1.6;}
  .converter{background:var(--card);border:1px solid var(--border);border-radius:6px;padding:26px;box-shadow:0 1px 3px rgba(0,0,0,0.06);}
  .row{display:flex;gap:16px;flex-wrap:wrap;align-items:flex-end;}
  .field{flex:1;min-width:150px;display:flex;flex-direction:column;gap:8px;}
  label{font-size:0.85rem;color:var(--muted);font-weight:600;text-transform:uppercase;letter-spacing:0.03em;}
  input[type=number], select{
    background:#fff;border:1px solid var(--border);color:var(--text);
    padding:12px 14px;border-radius:4px;font-size:1.05rem;width:100%;
  }
  select{cursor:pointer;}
  .swap{background:var(--accent);border:1px solid var(--accent);color:#fff;border-radius:4px;padding:12px 16px;cursor:pointer;font-size:1.2rem;height:48px;}
  .swap:hover{opacity:0.9;}
  .result{margin-top:22px;padding:18px 20px;background:#fbf3ee;border:1px solid #f0d9cc;border-radius:6px;font-size:1.25rem;line-height:1.6;}
  .result b{color:var(--accent2);}
  .note{font-size:0.85rem;color:var(--muted);margin-top:14px;line-height:1.6;}
  p{margin:0 0 14px;}
  ul{margin:0 0 14px;padding-left:22px;}
  li{margin-bottom:6px;}
  main a{color:var(--accent);font-weight:600;text-decoration:none;}
  main a:hover{text-decoration:underline;}
  .card{background:var(--card);border:1px solid var(--border);border-radius:6px;padding:18px 20px;margin-bottom:12px;box-shadow:0 1px 3px rgba(0,0,0,0.05);}
  .card h3{margin:0 0 8px;font-size:1.05rem;font-weight:700;}
  .card p{margin:0;color:var(--muted);font-size:0.95rem;line-height:1.65;}
  .stat-grid{display:flex;flex-wrap:wrap;gap:12px;margin-bottom:20px;}
  .stat{flex:1;min-width:140px;background:var(--card);border:1px solid var(--border);border-radius:6px;padding:14px 16px;box-shadow:0 1px 3px rgba(0,0,0,0.05);}
  .stat .k{font-size:0.75rem;color:var(--muted);text-transform:uppercase;letter-spacing:0.03em;}
  .stat .v{font-size:1.1rem;font-weight:700;margin-top:4px;}
  footer{text-align:center;padding:28px 20px;color:#cfcabd;font-size:0.88rem;border-top:1px solid var(--border);line-height:1.6;background:var(--headbar);}
  .updated{max-width:900px;margin:0 auto;padding:0 20px 4px;font-size:0.78rem;color:var(--muted);}
  .updated time{font-weight:600;color:var(--text);}
  footer a{color:#fff;}

  /* grouped dropdown navigation */
  nav details.navgroup{position:relative;}
  nav details.navgroup>summary{list-style:none;cursor:pointer;color:var(--text);font-size:1rem;font-weight:600;padding:16px 20px;border-bottom:3px solid transparent;user-select:none;}
  nav details.navgroup>summary::-webkit-details-marker{display:none;}
  nav details.navgroup>summary:hover{color:var(--accent);border-bottom-color:var(--accent);}
  nav details.navgroup[open]>summary{color:var(--accent);border-bottom-color:var(--accent);}
  nav .navmenu{position:absolute;left:0;top:100%;z-index:40;background:#fff;border:1px solid var(--border);border-radius:0 0 8px 8px;box-shadow:0 6px 18px rgba(0,0,0,0.12);min-width:280px;padding:8px 0;}
  nav .navmenu a{display:block;padding:9px 18px;font-size:0.92rem;font-weight:500;border-bottom:none;white-space:nowrap;}
  nav .navmenu a:hover{background:var(--bg);color:var(--accent);border-bottom:none;}
  nav .navmenu .navsep{border-top:1px solid var(--border);margin:6px 0;}
  nav .navmenu a.more{font-weight:700;color:var(--accent);}
  @media(max-width:700px){
    nav .navmenu{position:static;box-shadow:none;border:none;border-top:1px solid var(--border);border-radius:0;min-width:0;}
    nav details.navgroup{width:100%;}
    nav details.navgroup>summary{text-align:center;}
  }

  /* descriptive footer */
  footer{text-align:left;padding:34px 20px 22px;}
  .foot-cols{max-width:1100px;margin:0 auto;display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:26px;}
  .foot-cols h4{margin:0 0 10px;font-size:0.9rem;color:#fff;letter-spacing:0.02em;}
  .foot-cols a{display:block;color:#cfcabd;text-decoration:none;font-size:0.82rem;line-height:1.5;margin-bottom:8px;}
  .foot-cols a:hover{color:#fff;text-decoration:underline;}
  .foot-legal{max-width:1100px;margin:24px auto 0;padding-top:16px;border-top:1px solid rgba(255,255,255,0.15);text-align:center;font-size:0.8rem;color:#a9a49a;}

  .related-list{list-style:none;padding:0;margin:0;}
  .related-list li{padding:9px 0;border-bottom:1px solid var(--border);}
  .related-list li:last-child{border-bottom:none;}
  .related-list a{color:var(--accent);font-weight:700;text-decoration:none;}
  .related-list a:hover{text-decoration:underline;}
  .related-list .d{display:block;color:var(--muted);font-size:0.84rem;font-weight:400;margin-top:2px;line-height:1.5;}