:root{
  --ink:#16202e; --muted:#8a94a6; --line:#e6eaf0; --bg:#ffffff; --alt:#f6f8fb;
  --blue:#1d6fd0; --blue-d:#1558a8; --amber:#c07d0a; --green:#1a8f5f; --red:#d1483c;
  --r:14px; --shadow:0 2px 10px rgba(20,40,80,.06), 0 12px 32px rgba(20,40,80,.05);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;color:var(--ink);background:var(--bg);
  font:16px/1.65 -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue","PingFang SC","Microsoft YaHei",sans-serif;
  -webkit-font-smoothing:antialiased}
.wrap{max-width:1100px;margin:0 auto;padding:0 20px}
h1{font-size:clamp(28px,4vw,46px);line-height:1.18;margin:0 0 14px;letter-spacing:-.02em}
h2{font-size:clamp(21px,2.6vw,30px);margin:0 0 8px;letter-spacing:-.01em}
h3{margin:0 0 6px;font-size:16px}
p{margin:0 0 12px}
a{color:var(--blue);text-decoration:none}
a:hover{text-decoration:underline}
.muted{color:var(--muted)}
.tiny{font-size:13px}
b{font-weight:650}

/* ---- topbar ---- */
.topbar{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.92);backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
.topbar .wrap{display:flex;align-items:center;justify-content:space-between;height:60px}
.brand{display:flex;align-items:center;gap:8px;font-size:15px}
.brand .logo{font-size:19px}
.brand .sep{color:var(--line)}
.topbar nav{display:flex;align-items:center;gap:20px;font-size:14px}
.topbar nav a{color:#3a4657}
.topbar nav a:hover{color:var(--blue);text-decoration:none}
@media(max-width:1040px){.topbar nav{gap:14px}}
@media(max-width:760px){.topbar nav a:not(.btn){display:none}}

/* ---- 语言开关 EN | 中文 ---- */
.langsw{display:inline-flex;align-items:center;background:var(--alt);border:1px solid var(--line);
  border-radius:20px;padding:2px;gap:2px;flex:0 0 auto}
.langsw button{appearance:none;border:0;background:transparent;color:#5a6879;cursor:pointer;
  font:600 12.5px/1 inherit;font-family:inherit;padding:6px 11px;border-radius:16px;transition:.15s}
.langsw button:hover{color:var(--ink)}
.langsw button.on{background:var(--blue);color:#fff}
.langsw button:focus-visible{outline:2px solid var(--blue);outline-offset:1px}

/* ---- buttons ---- */
.btn{display:inline-flex;align-items:center;gap:7px;padding:11px 18px;border-radius:10px;border:1px solid var(--line);
  background:#fff;color:var(--ink);font-size:14.5px;font-weight:600;cursor:pointer;transition:.15s;white-space:nowrap}
.btn:hover{transform:translateY(-1px);box-shadow:var(--shadow);text-decoration:none}
.btn.primary{background:var(--blue);border-color:var(--blue);color:#fff}
.btn.primary:hover{background:var(--blue-d)}
.btn.ghost{background:transparent}
.btn.sm{padding:7px 13px;font-size:13px}

/* ---- hero ---- */
.hero{padding:52px 0 42px;background:
  radial-gradient(900px 380px at 12% -10%, #eaf2fd 0%, transparent 60%),
  radial-gradient(700px 340px at 92% 0%, #fdf3e6 0%, transparent 55%)}
.hero-grid{display:grid;grid-template-columns:1.15fr .85fr;gap:34px;align-items:start}
@media(max-width:880px){.hero-grid{grid-template-columns:1fr;gap:22px}}
.eyebrow{display:inline-block;font-size:12.5px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;
  color:var(--blue);background:#eaf2fd;border-radius:20px;padding:5px 12px;margin-bottom:14px}
.lede{font-size:17px;color:#3f4b5c;max-width:56ch}
.cta-row{display:flex;flex-wrap:wrap;gap:10px;margin:20px 0 10px}
.hero-card{background:#fff;border:1px solid var(--line);border-radius:var(--r);padding:20px 22px;box-shadow:var(--shadow)}
.hc-title{font-weight:700;margin-bottom:10px;font-size:15px}
.ticks{list-style:none;margin:0;padding:0}
.ticks li{position:relative;padding-left:24px;margin-bottom:9px;font-size:14.2px;color:#3f4b5c}
.ticks li:before{content:"✓";position:absolute;left:0;top:0;color:var(--green);font-weight:800}

/* ---- sections ---- */
.sec{padding:52px 0}
.sec.alt{background:var(--alt);border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.sec .sub{color:var(--muted);margin-bottom:22px;max-width:70ch}
.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(255px,1fr));gap:14px}
.card{background:#fff;border:1px solid var(--line);border-radius:var(--r);padding:18px;transition:.15s}
.card:hover{box-shadow:var(--shadow);transform:translateY(-2px)}
.card .ico{font-size:24px;display:block;margin-bottom:8px}
.card p{color:#4a5768;font-size:14.3px;margin:0}
.card .step{display:inline-block;font-size:11.5px;font-weight:700;letter-spacing:.06em;text-transform:uppercase;
  color:var(--muted);margin-bottom:6px}
.chips{display:flex;flex-wrap:wrap;gap:9px}
.chip{background:#fff;border:1px solid var(--line);border-radius:30px;padding:9px 15px;font-size:14.2px;display:flex;gap:7px;align-items:center}
.note{margin-top:18px;background:#fffaf0;border:1px solid #f0dfc0;border-left:4px solid var(--amber);
  border-radius:10px;padding:14px 16px;font-size:14.2px;color:#5a4a2a}

/* ---- faq ---- */
.faq details{background:#fff;border:1px solid var(--line);border-radius:10px;padding:14px 16px;margin-bottom:9px}
.faq summary{cursor:pointer;font-weight:620;font-size:15px}
.faq p{margin:10px 0 0;color:#4a5768;font-size:14.3px}

/* ---- contact ---- */
.contact{background:linear-gradient(180deg,#fff 0%,#f7fafd 100%)}
.contact-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:12px;margin-bottom:26px}
.cc{display:flex;gap:12px;align-items:flex-start;background:#fff;border:1px solid var(--line);border-radius:12px;
  padding:14px;cursor:pointer;transition:.15s}
.cc:hover{box-shadow:var(--shadow);transform:translateY(-2px);border-color:#cfe0f5}
.cc .ico{width:38px;height:38px;flex:0 0 38px;border-radius:10px;background:#eef4fd;display:flex;align-items:center;
  justify-content:center;font-size:19px;font-weight:700;color:var(--blue)}
.cc .nm{font-weight:650;font-size:14.5px}
.cc .vl{font-size:13px;color:#5a6879;word-break:break-all}
.cc .nt{font-size:12px;color:var(--muted);margin-top:2px}
.cc.primary{border-color:#cfe0f5;background:linear-gradient(180deg,#f7fbff,#fff)}
.cc.todo{opacity:.65}
.badge{display:inline-block;font-size:10.5px;font-weight:700;padding:1px 6px;border-radius:20px;background:#fdeceb;color:var(--red);margin-left:5px;vertical-align:1px}
.qr-block{background:#fff;border:1px solid var(--line);border-radius:var(--r);padding:20px;text-align:center}
.qr-title{font-weight:700;margin-bottom:14px}
.qr-row{display:flex;flex-wrap:wrap;gap:18px;justify-content:center}
.qr-item{width:132px}
.qr-item img{width:132px;height:132px;border:1px solid var(--line);border-radius:10px;background:#fff;padding:5px}
.qr-item .lb{font-size:12.5px;font-weight:600;margin-top:6px}
.qr-item .sb{font-size:11px;color:var(--muted)}

/* ---- footer / fab ---- */
.foot{padding:26px 0 40px;border-top:1px solid var(--line);background:#fff;font-size:14px}
.foot p{margin:0 0 5px}
.fab{position:fixed;right:20px;bottom:20px;width:54px;height:54px;border-radius:50%;background:var(--blue);color:#fff;
  display:flex;align-items:center;justify-content:center;font-size:24px;box-shadow:0 8px 22px rgba(29,111,208,.4);z-index:40}
.fab:hover{text-decoration:none;transform:scale(1.05)}

/* ---- kit builder (tools.html) ---- */
.builder{display:grid;grid-template-columns:1.1fr .9fr;gap:20px}
@media(max-width:880px){.builder{grid-template-columns:1fr}}
.fieldset{background:#fff;border:1px solid var(--line);border-radius:var(--r);padding:20px;margin-bottom:14px}
.fieldset h3{margin-bottom:12px;font-size:15px}
.opts{display:flex;flex-wrap:wrap;gap:8px}
.opt{border:1px solid var(--line);border-radius:30px;padding:8px 14px;font-size:13.8px;cursor:pointer;background:#fff;user-select:none}
.opt.on{background:var(--blue);border-color:var(--blue);color:#fff}
input[type=text],input[type=number],select{width:100%;padding:10px 12px;border:1px solid var(--line);border-radius:9px;font-size:14.5px;font-family:inherit}
label.lbl{display:block;font-size:13px;font-weight:600;margin:12px 0 5px;color:#4a5768}
.preview{background:#0f1724;color:#d7e3f4;border-radius:var(--r);padding:18px;font:13.5px/1.6 ui-monospace,Consolas,monospace;white-space:pre-wrap;word-break:break-word}
.preview .hl{color:#7fb2f0}
.kv{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:10px}
.kv .btn{flex:1}

/* ---- cookie 说明条 ---- */
.cookienote{position:fixed;left:0;right:0;bottom:0;z-index:60;display:flex;gap:12px;align-items:center;
  justify-content:center;flex-wrap:wrap;background:#182233;color:#dbe6f5;font-size:13.5px;padding:11px 18px}
.cookienote .btn{background:#2f80ed;border-color:#2f80ed;color:#fff}
@media print{.cookienote{display:none}}