:root{
  --blue:#1E7BF0; --blue-dark:#1466D8; --ink:#1e2733; --muted:#6b7688;
  --bg:#f5f8fd; --card:#ffffff; --line:#e6ecf5;
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{font-family:-apple-system,"PingFang SC","Microsoft YaHei",Segoe UI,sans-serif;color:var(--ink);background:var(--bg);line-height:1.6}
.wrap{max-width:1120px;margin:0 auto;padding:0 24px}
a{color:inherit;text-decoration:none}
code{font-family:ui-monospace,Menlo,Consolas,monospace}

/* buttons */
.btn{display:inline-block;border:none;border-radius:10px;padding:10px 18px;font-size:14px;cursor:pointer;transition:.15s}
.btn-lg{padding:13px 26px;font-size:15px}
.btn-primary{background:var(--blue);color:#fff}
.btn-primary:hover{background:var(--blue-dark)}
.btn-ghost{background:transparent;color:var(--blue);border:1px solid var(--blue)}
.btn-ghost:hover{background:#eaf2ff}
.btn-white{background:#fff;color:var(--blue);font-weight:600}
.btn-white:hover{background:#eef4ff}

/* nav */
.nav{position:sticky;top:0;z-index:20;background:rgba(255,255,255,.9);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.nav-inner{display:flex;align-items:center;height:64px;gap:28px}
.brand{font-size:22px;font-weight:800;color:var(--ink)}
.brand span{color:var(--blue)}
.nav-links{display:flex;gap:26px;margin-left:8px}
.nav-links a{color:var(--muted);font-size:15px}
.nav-links a:hover{color:var(--blue)}
.nav .btn{margin-left:auto}

/* hero */
.hero{background:linear-gradient(180deg,#eaf3ff 0%,#f5f8fd 70%)}
.hero-inner{display:grid;grid-template-columns:1.1fr .9fr;gap:48px;align-items:center;padding:64px 24px}
.hero-copy h1{font-size:42px;line-height:1.2;font-weight:800;letter-spacing:.5px}
.lead{font-size:18px;color:#39465a;margin:16px 0 20px}
.hero-points{list-style:none;margin:0 0 26px}
.hero-points li{position:relative;padding-left:22px;color:#33465e;margin:8px 0}
.hero-points li::before{content:"✓";position:absolute;left:0;color:var(--blue);font-weight:800}
.hero-cta{display:flex;gap:14px;flex-wrap:wrap}

/* demo card */
.demo-card{background:var(--card);border:1px solid var(--line);border-radius:16px;box-shadow:0 12px 40px rgba(30,123,240,.12);overflow:hidden}
.demo-head{background:var(--blue);color:#fff;padding:12px 18px;font-size:14px;display:flex;align-items:center;gap:8px}
.demo-head .dot{width:8px;height:8px;border-radius:50%;background:#7CFF9B;display:inline-block}
.demo-chat{height:280px;overflow-y:auto;padding:16px;display:flex;flex-direction:column;gap:10px;background:#fafcff}
.msg{max-width:80%;padding:9px 13px;border-radius:12px;font-size:14px;white-space:pre-wrap}
.msg.bot{align-self:flex-start;background:#eef3f9;color:#2c2f36}
.msg.me{align-self:flex-end;background:var(--blue);color:#fff}
.demo-input{display:flex;gap:8px;padding:12px;border-top:1px solid var(--line);background:#fff}
.demo-input input{flex:1;border:1px solid var(--line);border-radius:10px;padding:10px 12px;font-size:14px;outline:none}
.demo-input input:focus{border-color:var(--blue)}

/* sections */
.section{padding:64px 0}
.section.alt{background:#fff}
.sec-title{font-size:30px;font-weight:800;text-align:center}
.sec-title.left{text-align:left}
.sec-sub{text-align:center;color:var(--muted);margin-top:8px;margin-bottom:34px}
.grid{display:grid;gap:18px}

/* platforms */
.platforms{grid-template-columns:repeat(4,1fr)}
.plat{display:flex;align-items:center;gap:12px;background:var(--card);border:1px solid var(--line);border-radius:14px;padding:16px 18px;transition:.15s}
.plat:hover{border-color:#bcd8ff;box-shadow:0 8px 24px rgba(30,123,240,.1);transform:translateY(-2px)}
.plat img{width:40px;height:40px;object-fit:contain}
.plat b{display:block;font-size:15px}
.plat span{font-size:12px;color:var(--muted)}

/* features / value / advantage */
.features{grid-template-columns:repeat(4,1fr)}
.value{grid-template-columns:repeat(3,1fr)}
.advantage{grid-template-columns:repeat(5,1fr)}
.feat{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:24px 20px}
.feat-ico{font-size:30px}
.feat h3{font-size:17px;margin:12px 0 8px}
.feat p{font-size:14px;color:#4a5668}

/* api */
.api-inner{display:grid;grid-template-columns:1fr 1fr;gap:40px;align-items:center}
.api-copy p{color:#4a5668;margin:12px 0 16px}
.api-copy code{background:#eaf2ff;color:var(--blue-dark);padding:2px 6px;border-radius:5px}
.code{background:#0f1b2d;color:#cfe0ff;border-radius:14px;padding:22px;font-size:13px;overflow:auto;line-height:1.7}

/* service */
.service{grid-template-columns:repeat(4,1fr)}
.svc{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:22px;text-align:center}
.svc b{display:block;font-size:16px;color:var(--blue)}
.svc span{font-size:13px;color:var(--muted)}

/* cta */
.cta{background:linear-gradient(90deg,var(--blue),#5aa3ff);color:#fff}
.cta-inner{padding:56px 24px;text-align:center}
.cta h2{font-size:28px;font-weight:800}
.cta p{margin:10px 0 22px;opacity:.95}
.contact{display:inline-flex;align-items:center;gap:22px;background:#fff;border-radius:16px;padding:20px 26px;color:var(--ink);box-shadow:0 14px 40px rgba(0,0,0,.15)}
.qr{width:150px;height:150px;border-radius:12px;overflow:hidden;background:#f2f5fa;display:flex;align-items:center;justify-content:center;flex:0 0 auto}
.qr img{width:100%;height:100%;object-fit:contain}
.qr-empty::after{content:"请放置 web/img/wechat-qr.png";font-size:12px;color:#98a2b3;text-align:center;padding:10px}
.contact-info{text-align:left}
.wx-label{color:var(--muted);font-size:13px}
.wx-id{font-size:22px;font-weight:800;color:var(--blue);margin:6px 0 8px}
.wx-tip{font-size:13px;color:var(--muted)}
@media (max-width:520px){.contact{flex-direction:column;text-align:center}.contact-info{text-align:center}}

/* footer */
.footer{background:#0f1b2d;color:#c8d3e4}
.footer-inner{padding:26px 24px;display:flex;justify-content:space-between;flex-wrap:wrap;gap:10px;font-size:14px}
.muted{color:#8a9bb4}

@media (max-width:1000px){
  .advantage{grid-template-columns:repeat(3,1fr)}
}
@media (max-width:900px){
  .hero-inner,.api-inner{grid-template-columns:1fr}
  .platforms,.features,.service,.value,.advantage{grid-template-columns:repeat(2,1fr)}
  .nav-links{display:none}
  .hero-copy h1{font-size:32px}
}