:root{
      --bg:#f0f4f8; --text:#142032; --muted:#5c6b7a; --card:#ffffff; --line:#e5eef6;
      --brand:#0d47a1; --brand-600:#0b3a8a; --focus:#2bd4a7; --shadow:0 6px 24px rgba(20,32,50,.08);
    }
    *{box-sizing:border-box}
    html{scroll-behavior:smooth}
    body{
      margin:0; background:var(--bg); color:var(--text);
      font:16px/1.6 Inter,system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Ubuntu,sans-serif;
      display: flex; justify-content: center; padding: 2rem 1rem;
    }
    .body-wrapper {
      width:min(100%, 1240px); background: var(--card);
      border-radius: 20px; box-shadow: 0 10px 40px rgba(0,0,0,0.1); overflow: clip;
      margin-inline:auto;
    }
    .container{width:min(calc(100% - 2rem),1100px);margin-inline:auto;padding:0}
    .skip{position:absolute;left:-9999px}
    .skip:focus{left:1rem;top:1rem;background:#fff;color:#000;padding:.5rem .75rem;border-radius:.5rem;z-index:1000}
    header.site{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.9);backdrop-filter:saturate(140%) blur(8px);border-bottom:1px solid var(--line)}
    .brand{display:flex;gap:.6rem;align-items:center;font-weight:800; color: var(--brand)}
    .brand .dot{width:10px;height:10px;border-radius:999px;background:var(--brand)}
    nav ul{list-style:none;margin:0;padding:0;display:flex;gap:.8rem;flex-wrap:wrap}
    nav a{color:var(--text);text-decoration:none;padding:.45rem .6rem;border-radius:.6rem}
    nav a:hover, nav a:focus{background:rgba(13,71,161,.08);outline:none}
    .hero{padding:2.25rem 0 1rem; text-align: center;}
    .hero h1{font-size:clamp(1.8rem,3vw+1rem,2.8rem);line-height:1.2;margin:.2rem 0}
    .lead{max-width:70ch;color:var(--muted); margin-inline: auto;}
    .support-banner{
      display:grid;grid-template-columns:auto 1fr auto;align-items:center;gap:1rem;
      margin:1rem auto 1.5rem;padding:1rem 1.15rem;border:1px solid #b9d5ff;border-radius:16px;
      background:linear-gradient(135deg,#eef6ff 0%,#f5fffb 100%);box-shadow:var(--shadow);
    }
    .support-icon{display:grid;place-items:center;width:44px;height:44px;border-radius:12px;background:#fff;color:var(--brand);font-size:1.35rem;box-shadow:0 4px 14px rgba(13,71,161,.12)}
    .support-copy strong{display:block;font-size:1.05rem;margin-bottom:.15rem}
    .support-copy p{margin:0;color:var(--muted)}
    .support-banner .btn{white-space:nowrap;text-decoration:none;text-align:center}
    .card{background:var(--card);border:none;border-radius:16px;box-shadow:none;padding:1.5rem;margin:1rem auto}
    .container.card { border: 1px solid var(--line); box-shadow: var(--shadow); padding:1.5rem; }
    .grid-2{display:grid;grid-template-columns:1fr 1fr;gap:.75rem}
    .grid-2 .full{grid-column:1/-1}
    label{display:block;font-weight:600;margin-bottom:.25rem}
    .field-hint{display:block;margin-top:.3rem;color:var(--muted);font-size:.875rem}
    input, select{width:100%;padding:.65rem .7rem;border-radius:.7rem;border:1px solid var(--line);background:#fcfdff;color:var(--text)}
    input:focus, select:focus{outline:2px solid var(--focus);outline-offset:2px}
    input[aria-invalid="true"]{border-color:#b42318;background:#fff7f6}
    .actions{display:flex;gap:.5rem;flex-wrap:wrap}
    .btn{border:1px solid var(--line);background:#fff;border-radius:.7rem;padding:.55rem .9rem;cursor:pointer;font-weight:600; transition: all 0.2s ease;}
    .btn:hover{border-color:#cfe0ef; transform: translateY(-2px);}
    .btn-primary{background:var(--brand);color:#fff;border-color:var(--brand-600)}
    .table-wrap{overflow:auto;border:1px solid var(--line);border-radius:12px}
    table{width:100%;border-collapse:collapse}
    th, td{padding:.6rem .7rem;border-bottom:1px solid var(--line);text-align:left}
    th{position:sticky;top:0;background:#f3f7fb;font-weight:700}
    .metrics{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:.75rem;margin:.75rem 0}
    .metric{background:#f6fbff;border:1px solid var(--line);border-radius:12px;padding:.65rem}
    .metric strong{display:block;font-size:1.05rem}
    #chart-container { position: relative; width: 100%; margin-top: 1rem; }
    #chart-container.chart-ready{height:500px}
    .chart-status{margin:.75rem 0;color:var(--muted);text-align:center}
    .equation{display:flex;justify-content:center;gap:2.5rem;flex-wrap:wrap;margin:1.25rem 0;font-size:1.08rem}
    .fraction{display:inline-flex;flex-direction:column;vertical-align:middle;text-align:center;line-height:1.2}
    .fraction .top{border-bottom:1px solid currentColor;padding:0 .2rem .12rem}
    .fraction .bottom{padding:.12rem .2rem 0}
    canvas{border:1px solid var(--line);border-radius:12px;background:#fff}
    article ul, article ol { padding-left: 20px; }
    article h3, article h4 { margin-top: 2rem; border-bottom: 1px solid var(--line); padding-bottom: 0.5rem; color: var(--brand); }
    article h4 { font-size: 1.1rem; border-bottom-style: dashed; margin-top: 1.5rem; }
    .section-lead{margin:.25rem 0 1rem;color:var(--muted)}
    .info-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:1rem}
    .info-card{border:1px solid var(--line);border-radius:14px;background:#fbfdff;padding:1rem}
    .info-card h3{margin:.1rem 0 .5rem;font-size:1.02rem;color:var(--text);border:none;padding:0}
    .info-card p,.info-card li{color:var(--muted)}
    .info-card ul{margin:.5rem 0 0;padding-left:1.1rem}
    .check-list{margin:0;padding-left:1.1rem}
    .contact-list{display:grid;gap:.55rem}
    .contact-item{display:flex;gap:.6rem;align-items:flex-start;padding:.8rem .9rem;border:1px solid var(--line);border-radius:12px;background:#fbfdff}
    .contact-item strong{display:block;color:var(--text)}
    .contact-item span,.contact-item a{color:var(--muted);text-decoration:none}
    .contact-item a:hover{text-decoration:underline}
    .notice{margin-top:1rem;padding:.9rem 1rem;border-radius:12px;background:#fff8e8;border:1px solid #f4d28b;color:#7a5600}
    .footer-links,.legal-links{display:flex;justify-content:center;gap:.75rem;flex-wrap:wrap;margin:.35rem 0}
    .footer-links a,.legal-links a{color:var(--muted);text-decoration:none}
    .footer-links a:hover,.legal-links a:hover{text-decoration:underline}
    footer{border-top:1px solid var(--line);color:var(--muted); text-align: center; padding: 1.5rem 1rem;}
    @media (max-width:720px){
      body{padding:0;background:var(--card)}
      .body-wrapper{border-radius:0;box-shadow:none}
      .grid-2{grid-template-columns:1fr}
      nav ul{gap:.25rem}
      nav a{padding:.4rem}
      .support-banner{grid-template-columns:auto 1fr}
      .support-banner .btn{grid-column:1/-1;width:100%}
      #chart-container.chart-ready{height:380px}
    }
    .page-hero{padding:2rem 0 .75rem}
    .page-hero h1{font-size:clamp(1.8rem,3vw,2.6rem);line-height:1.2;margin:.2rem 0}
    .breadcrumbs{font-size:.9rem;color:var(--muted);margin-bottom:.65rem}
    .breadcrumbs a{color:var(--brand);text-decoration:none}
    .breadcrumbs a:hover{text-decoration:underline}
    .byline{display:flex;gap:.8rem;flex-wrap:wrap;color:var(--muted);font-size:.92rem;margin:.4rem 0 1.2rem}
    .article-list{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:1rem}
    .article-card{display:flex;flex-direction:column;border:1px solid var(--line);border-radius:14px;padding:1rem;background:#fbfdff}
    .article-card h3{margin:.1rem 0 .45rem;color:var(--text);border:none;padding:0}
    .article-card p{color:var(--muted);margin:.1rem 0 .9rem}
    .article-card a{margin-top:auto;color:var(--brand);font-weight:700;text-decoration:none}
    .article-card a:hover{text-decoration:underline}
    .reference-list{font-size:.94rem;color:var(--muted)}
    .reference-list a{color:var(--brand)}
    details.faq{border:1px solid var(--line);border-radius:12px;padding:.75rem .9rem;background:#fbfdff;margin:.65rem 0}
    details.faq summary{cursor:pointer;font-weight:700}
    details.faq p{color:var(--muted);margin:.65rem 0 .15rem}
    .legal-card h2:first-child,.content-card h2:first-child{margin-top:.1rem}
    .content-card h2{margin-top:2rem;color:var(--brand)}
    .content-card h3{margin-top:1.5rem}
    .content-card p,.content-card li{max-width:78ch}
    .content-card a{color:var(--brand)}
    .form-grid{display:grid;grid-template-columns:1fr 1fr;gap:.85rem}
    .form-grid .full{grid-column:1/-1}
    textarea{width:100%;min-height:160px;resize:vertical;padding:.7rem;border-radius:.7rem;border:1px solid var(--line);background:#fcfdff;color:var(--text);font:inherit}
    textarea:focus{outline:2px solid var(--focus);outline-offset:2px}
    .status-message{padding:.85rem 1rem;border-radius:12px;margin:0 0 1rem}
    .status-success{background:#effcf6;border:1px solid #8ee0bb;color:#176b4b}
    .status-error{background:#fff4f2;border:1px solid #f1aaa2;color:#8a271d}
    .honeypot{position:absolute;left:-9999px;width:1px;height:1px;overflow:hidden}
    .disclosure{font-size:.86rem;color:var(--muted);margin:.35rem 0 0}
    .nav-current{background:rgba(13,71,161,.08);font-weight:700}
    @media (max-width:720px){
      .form-grid{grid-template-columns:1fr}
      header.site .container{align-items:flex-start!important;flex-direction:column}
      nav{width:100%;overflow-x:auto}
      nav ul{flex-wrap:nowrap;min-width:max-content}
    }

.brand{text-decoration:none}
code{font-family:ui-monospace,SFMono-Regular,Consolas,monospace;font-size:.92em}