:root{
  --bg:#f6f7fb; --card:#ffffff; --border:#e6e8ee; --text:#111827; --muted:#6b7280;
  --primary:#574cf7; --teal:#06b6d4; --accent:#3b82f6; --success:#22c55e; --green:#16a34a; --danger:#ef4444;
  --radius:14px; --shadow:0 10px 24px rgba(17,24,39,.08), 0 1px 2px rgba(17,24,39,.06);
}
*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  font-family:ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,"Noto Sans";
  color:var(--text);
  background:radial-gradient(1200px 800px at 20% -20%, #eef2ff 0%, transparent 60%), var(--bg);
  line-height:1.45;
  -webkit-tap-highlight-color: rgba(0,0,0,0);
}
.visually-hidden{position:absolute!important;width:1px;height:1px;overflow:hidden;clip:rect(1px,1px,1px,1px);white-space:nowrap}
.skip-link{position:absolute;left:-9999px;top:auto;width:1px;height:1px;overflow:hidden}
.skip-link:focus{left:12px;top:12px;width:auto;height:auto;padding:8px 10px;background:#111827;color:#fff;border-radius:8px;z-index:9999}

header.site{max-width:1100px;margin:0 auto;padding:16px 20px 0}
nav#toc{display:flex;gap:10px;margin:6px auto 16px;flex-wrap:wrap;justify-content:center;max-width:1000px}
nav#toc a{font-weight:600;color:#374151;background:#eef2ff;border:1px solid #dfe4ff;padding:6px 10px;border-radius:8px;text-decoration:none;white-space:nowrap}
nav#toc a:hover{background:#e4e9ff}
@media (max-width:640px){
  nav#toc{flex-wrap:nowrap;overflow-x:auto;-webkit-overflow-scrolling:touch;scroll-snap-type:x proximity;justify-content:flex-start}
  nav#toc a{scroll-snap-align:start}
}

.page{max-width:940px;margin:20px auto 80px;padding:0 20px}
h1{font-size:clamp(26px,4vw,40px);margin:0 0 10px;letter-spacing:-.02em;text-align:center}
.subhead{text-align:center;color:var(--muted);max-width:740px;margin:0 auto 18px}

.card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);overflow:hidden;margin-bottom:28px}
.card .ribbon{background:var(--primary);color:#fff;padding:14px 18px;font-weight:600;display:flex;align-items:center;gap:5px;text-align:left;flex-wrap:wrap;justify-content:center;align-items:left}
.ribbon .dot{width:22px;height:22px;border-radius:6px;display:inline-grid;place-items:center;background:rgba(255,255,255,.18);box-shadow:inset 0 0 0 1px rgba(255,255,255,.25)}
.ribbon svg{opacity:.9}
.card .body{padding:18px}
.card .ribbon strong{white-space:nowrap}

.tabs{display:flex;gap:10px;margin-bottom:14px;border-bottom:1px dashed var(--border);padding-bottom:8px;flex-wrap:wrap}
.tab{appearance:none;border:1px solid var(--border);background:#fafbff;color:#374151;padding:7px 12px;border-radius:9px;font-weight:600;cursor:pointer;transition:.15s}
.tab[aria-selected="true"]{background:#edeaff;border-color:#d7d3ff;color:#312e81}

.stack{display:grid;grid-template-columns:repeat(12,1fr);gap:14px}
.col-3{grid-column:span 3}.col-4{grid-column:span 4}.col-5{grid-column:span 5}.col-6{grid-column:span 6}.col-8{grid-column:span 8}.col-12{grid-column:span 12}
@media (max-width:860px){.stack{grid-template-columns:repeat(6,1fr)} .col-6,.col-5,.col-4,.col-3,.col-8{grid-column:span 6}}

label{font-size:.92rem;color:#374151;font-weight:600;display:block;margin-bottom:6px}
.field{display:flex;gap:8px;align-items:center;flex-wrap:wrap}

input[type="number"],select{
  width:100%;padding:11px 12px;border:1px solid var(--border);border-radius:10px;background:#fff;color:#111827;font-size:16px;outline:none;transition:.15s;
  -moz-appearance:textfield;
}
input[type="number"]:focus,select:focus{border-color:var(--accent);box-shadow:0 0 0 3px rgba(59,130,246,.14)}
input[type="number"]::-webkit-outer-spin-button,input[type="number"]::-webkit-inner-spin-button{appearance:none;margin:0}
input[type="number"]{appearance:textfield}

.unit{min-width:72px;text-align:center;padding:.45rem .6rem;background:#f8fafc;border:1px solid var(--border);color:#334155;border-radius:9px}
.radios{display:flex;gap:16px;margin-top:10px;flex-wrap:wrap}
.radio{display:flex;align-items:center;gap:8px;cursor:pointer;user-select:none;padding:7px 10px;border:1px solid var(--border);border-radius:10px;background:#fff}
.radio input{accent-color:var(--primary)}

.actions{display:flex;gap:10px;margin-top:10px;flex-wrap:wrap}
.btn{appearance:none;border:none;cursor:pointer;border-radius:10px;padding:11px 14px;font-weight:700;letter-spacing:.01em;display:inline-flex;align-items:center;gap:8px}
.btn svg{width:16px;height:16px}.btn-primary{background:#22c55e;color:#fff}.btn-ghost{background:#f3f4f6;color:#111827}.btn:disabled{opacity:.6;cursor:not-allowed}
@media (max-width:560px){.actions .btn{flex:1 1 180px}}
.muted{color:var(--muted)}.hidden{display:none !important}
.err{border-color:var(--danger) !important;box-shadow:0 0 0 3px rgba(239,68,68,.14) !important}

.field > input.compact{width:auto;flex:1 1 100px;min-width:84px}
@media (max-width:520px){.field > input.compact{flex:1 1 80px;min-width:74px}}

.result{margin-top:12px;border-top:1px dashed var(--border);padding-top:12px;display:grid;gap:10px}
.pill{display:flex;align-items:center;justify-content:space-between;gap:8px;border:1px solid var(--border);background:#fff;border-radius:12px;padding:10px 12px}
.pill .k{color:#4b5563;font-weight:600}.pill .v{font-variant-numeric:tabular-nums;font-weight:800}

.classic{margin-top:18px;border:1px solid #dbe6d3;border-radius:10px;overflow:hidden}
.classic .hdr{background:var(--green);color:#fff;padding:10px 14px;font-weight:800}
.classic .content{padding:12px;background:#fbfff9}
.classic .rows{display:grid;gap:8px;margin-bottom:10px}
.classic .row{display:grid;grid-template-columns:1fr auto auto;gap:8px;align-items:center;background:#fff;border:1px solid #e4efdc;border-radius:8px;padding:8px 10px}
.classic .row .val{font-weight:800;font-variant-numeric:tabular-nums}
.classic .row .pct{background:#eaf7e2;border:1px solid #d7e9cb;border-radius:6px;padding:4px 8px;font-weight:700;color:#14532d}
.section-title{font-weight:800;margin:12px 0 6px}
.classic table{width:100%;border-collapse:collapse;background:#fff;border:1px solid #e4efdc;border-radius:8px;overflow:hidden}
.classic th,.classic td{border:1px solid #e4efdc;padding:8px 10px;text-align:left;white-space:nowrap}
.classic th{background:#f1f8ec}
.hint{color:#475569;font-size:.95rem;margin:8px 0}

section.content{background:#fff;border:1px solid var(--border);border-radius:14px;box-shadow:var(--shadow);padding:18px;margin:24px 0}
section.content h2{margin:6px 0 8px}
section.content h3{margin:14px 0 6px}
section.content p{margin:8px 0;color:#1f2937}
section.content ul{margin:8px 0 8px 18px}
section.content table{width:100%;border-collapse:collapse;border:1px solid #e5e7eb;display:block;overflow-x:auto;-webkit-overflow-scrolling:touch}
section.content th,section.content td{border:1px solid #e5e7eb;padding:8px 10px;white-space:nowrap}
section.content th{background:#f8fafc;text-align:left}

details.settings summary{display:flex;align-items:center;gap:8px;cursor:pointer;font-weight:700;padding:8px 10px;border:1px solid var(--border);border-radius:10px;background:#fafbff}
details.settings[open] summary{background:#f5f3ff;border-color:#d7d3ff}
details.settings .inner{padding-top:12px}

.ribbon-teal{background:#06b6d4}
.converter .row{display:flex;gap:8px;align-items:center}
.converter .row .equals{font-weight:800;font-size:22px;margin:0 8px}
.output{min-width:160px;background:#f8fafc;border:1px solid var(--border);border-radius:10px;padding:11px 12px;font-weight:800;text-align:right}

.help{margin-top:14px;padding:10px 12px;border-left:4px solid #c7f9cc;background:#f7fff8;border:1px solid #e7f7ea;border-radius:10px}
.help h4{margin:0 0 6px}

footer{max-width:940px;margin:40px auto 50px;padding:0 20px;color:#6b7280}
footer a{color:#4f46e5;text-decoration:none}

/* Smooth in-page scrolling and anchor offset */
html{scroll-behavior:smooth}
[id]{scroll-margin-top:14px}
@media (prefers-reduced-motion: reduce){html{scroll-behavior:auto}}