:root{
  --bg:#f7f9fd; --surface:#ffffff; --ink:#1c2333; --muted:#5b6373;
  --primary:#2563eb; --primary-dark:#1d4ed8; --violet:#0ea5b7; --line:#e2e9f5;
  --soft:#eef4ff; --radius:16px; --shadow:0 10px 30px rgba(37,99,235,.10);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font-family:system-ui,-apple-system,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;background:var(--bg);color:var(--ink);line-height:1.6}
.wrap{max-width:1080px;margin:0 auto;padding:0 20px}
a{color:var(--primary-dark)}
.site-header{background:var(--surface);border-bottom:1px solid var(--line);position:sticky;top:0;z-index:30}
.header-inner{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:12px 20px}
.logo{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--ink);font-weight:800;font-size:1.3rem}
.logo-badge{width:36px;height:36px;border-radius:10px;background:linear-gradient(135deg,#2563eb,#0ea5b7);color:#fff;display:flex;align-items:center;justify-content:center;font-weight:800;font-size:.92rem;letter-spacing:.02em}
.logo em{font-style:normal;background:linear-gradient(45deg,#2563eb,#0ea5b7);-webkit-background-clip:text;background-clip:text;color:transparent}
.main-nav{display:flex;gap:22px}
.main-nav a{color:var(--ink);text-decoration:none;font-weight:600;font-size:.98rem}
.main-nav a:hover{color:var(--primary)}
.nav-toggle{display:none;background:none;border:0;font-size:1.5rem;cursor:pointer;color:var(--ink)}
.hero{background:linear-gradient(160deg,#fff 0%,var(--soft) 100%);border-bottom:1px solid var(--line);padding:52px 0 38px;text-align:center}
.hero h1{font-size:2.35rem;line-height:1.15;margin:0 0 12px}
.hero h1 .grad{background:linear-gradient(45deg,#2563eb,#0ea5b7);-webkit-background-clip:text;background-clip:text;color:transparent}
.hero p.lede{color:var(--muted);font-size:1.1rem;max-width:640px;margin:0 auto 24px}
.tool-card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:24px;max-width:860px;margin:0 auto;text-align:left}
.tool-card label{font-weight:700;display:block;margin-bottom:8px}
.text-input{width:100%;padding:15px 16px;font-size:1.05rem;border:2px solid var(--line);border-radius:12px;background:#fbfcff;color:var(--ink);font-family:inherit}
textarea.text-input{resize:vertical;min-height:74px}
.text-input:focus{outline:none;border-color:var(--primary)}
select.text-input{appearance:auto}
.tool-hint{color:var(--muted);font-size:.9rem;margin:10px 0 0;text-align:center}
.field-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px;margin-top:16px}
.field-grid.two{grid-template-columns:repeat(2,1fr)}
.field-grid label{font-size:.92rem;margin-bottom:6px}
.color-input{width:100%;height:50px;padding:4px;border:2px solid var(--line);border-radius:12px;background:#fbfcff;cursor:pointer}
.qr-stage{margin-top:20px;border:1px dashed var(--line);border-radius:12px;background:#fff;padding:22px;display:flex;flex-direction:column;align-items:center;gap:8px}
.qr-stage .qr-box{line-height:0}
.qr-stage .qr-box img,.qr-stage .qr-box canvas{max-width:100%;height:auto}
.qr-empty{color:var(--muted);font-size:.98rem;text-align:center;padding:18px 10px;line-height:1.5}
.qr-error{display:none;width:100%;background:#fdf0f0;border:1px solid #f3c2c2;color:#8f2323;border-radius:10px;padding:10px 14px;font-size:.94rem}
.btn-row{display:flex;gap:12px;flex-wrap:wrap;justify-content:center;margin-top:18px}
.toast{position:fixed;left:50%;bottom:26px;transform:translateX(-50%) translateY(20px);background:#1c2333;color:#fff;padding:11px 22px;border-radius:999px;font-weight:700;opacity:0;pointer-events:none;transition:opacity .2s,transform .2s;z-index:50}
.toast.show{opacity:1;transform:translateX(-50%) translateY(0)}
.btn{display:inline-block;background:var(--primary);color:#fff;border:0;border-radius:12px;padding:12px 24px;font-size:1rem;font-weight:700;cursor:pointer;text-decoration:none}
.btn:hover{background:var(--primary-dark)}
.btn.secondary{background:#fff;color:var(--primary-dark);border:2px solid var(--primary)}
.btn.secondary:hover{background:var(--soft)}
section.block{padding:44px 0}
section.block h2{font-size:1.55rem;margin:0 0 10px}
section.block .sub{color:var(--muted);max-width:720px}
.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin-top:20px}
.grid.two{grid-template-columns:repeat(2,1fr)}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:20px}
.card h3{margin:0 0 6px;font-size:1.05rem}
.card p{margin:0;color:var(--muted);font-size:.95rem}
.step-num{display:inline-flex;width:30px;height:30px;border-radius:50%;background:linear-gradient(135deg,#2563eb,#0ea5b7);color:#fff;align-items:center;justify-content:center;font-weight:800;margin-bottom:8px}
details.faq{background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:14px 18px;margin-top:10px}
details.faq summary{font-weight:700;cursor:pointer}
details.faq p{color:var(--muted);margin:8px 0 2px}
article.page{padding:40px 0 56px;max-width:820px}
article.page h1{font-size:2rem;line-height:1.25}
article.page h2{margin-top:30px;font-size:1.3rem}
article.page p,article.page li{color:#333a4a}
article.page ol,article.page ul{padding-left:22px}
article.page code{background:var(--soft);border:1px solid var(--line);border-radius:6px;padding:1px 6px;font-size:.92em;word-break:break-all}
.site-footer{background:#161c2b;color:#c9cfdd;margin-top:20px}
.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:24px;padding:38px 20px 10px}
.footer-grid a{color:#c9cfdd;text-decoration:none;display:block;padding:3px 0;font-size:.94rem}
.footer-grid a:hover{color:#fff}
.footer-brand{color:#fff;font-weight:800;font-size:1.15rem;margin:0 0 6px}
.footer-h{color:#fff;font-weight:700;margin:0 0 8px}
.footer-bottom{border-top:1px solid #2b3247;padding:14px 20px 22px;font-size:.85rem;color:#99a1b5}
@media (max-width:820px){
  .grid,.grid.two,.footer-grid,.field-grid,.field-grid.two{grid-template-columns:1fr}
  .hero h1{font-size:1.75rem}
  .main-nav{display:none;position:absolute;top:60px;right:16px;background:#fff;border:1px solid var(--line);border-radius:12px;box-shadow:var(--shadow);flex-direction:column;padding:14px 18px;gap:12px}
  .main-nav.open{display:flex}
  .nav-toggle{display:block}
}