/* ===== reset & tokens ===== */
*,*::before,*::after{box-sizing:border-box}
:root{
  --ink:#0f172a;
  --ink-2:#3f4a5f;
  --ink-3:#6b7688;
  --line:#e4e8ef;
  --bg:#ffffff;
  --bg-alt:#f7f9fc;
  --brand:#1a5cff;
  --brand-dark:#0d3fc4;
  --brand-soft:#eef3ff;
  --ok:#0f8a4d;
  --err:#c02626;
  --radius:14px;
  --shadow:0 1px 2px rgba(15,23,42,.05),0 8px 24px rgba(15,23,42,.06);
  --shadow-lg:0 2px 4px rgba(15,23,42,.06),0 16px 48px rgba(15,23,42,.1);
}
html{scroll-behavior:smooth}
body{
  margin:0;background:var(--bg);color:var(--ink);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei","Helvetica Neue",Arial,sans-serif;
  font-size:16px;line-height:1.75;-webkit-font-smoothing:antialiased;
}
img{max-width:100%;display:block}
a{color:var(--brand);text-decoration:none}
a:hover{text-decoration:underline}
h1,h2,h3{line-height:1.3;letter-spacing:-.01em;margin:0}
.wrap{max-width:1120px;margin:0 auto;padding:0 24px}
.wrap.narrow{max-width:760px}

/* ===== nav ===== */
.nav{
  position:sticky;top:0;z-index:50;background:rgba(255,255,255,.88);
  backdrop-filter:saturate(180%) blur(12px);border-bottom:1px solid var(--line);
}
.nav-inner{display:flex;align-items:center;gap:28px;height:64px}
.logo{font-weight:700;font-size:17px;color:var(--ink);letter-spacing:-.02em;flex-shrink:0}
.logo:hover{text-decoration:none}
.logo span{color:var(--ink-3);font-weight:500}
.nav-links{display:flex;gap:26px;margin-left:auto;font-size:14.5px}
.nav-links a{color:var(--ink-2)}
.nav-links a:hover{color:var(--brand);text-decoration:none}

/* ===== buttons ===== */
.btn{
  display:inline-block;padding:12px 24px;border-radius:10px;
  background:var(--brand);color:#fff;font-weight:600;font-size:15px;
  border:1px solid var(--brand);cursor:pointer;text-align:center;
  transition:background .15s,transform .1s,box-shadow .15s;
  font-family:inherit;
}
.btn:hover{background:var(--brand-dark);border-color:var(--brand-dark);text-decoration:none;color:#fff}
.btn:active{transform:translateY(1px)}
.btn-sm{padding:8px 16px;font-size:14px;flex-shrink:0}
.btn-lg{padding:15px 32px;font-size:16.5px}
.btn-block{display:block;width:100%}
.btn-ghost{background:#fff;color:var(--ink);border-color:var(--line)}
.btn-ghost:hover{background:var(--bg-alt);color:var(--ink);border-color:#cfd6e2}
.btn:disabled{opacity:.55;cursor:not-allowed}

/* ===== hero ===== */
.hero{padding:84px 0 72px;background:linear-gradient(180deg,var(--brand-soft) 0%,#fff 78%)}
.eyebrow{
  display:inline-block;margin:0 0 18px;padding:5px 13px;border-radius:999px;
  background:#fff;border:1px solid #d3ddf5;color:var(--brand-dark);
  font-size:13.5px;font-weight:600;letter-spacing:.01em;
}
.hero h1{font-size:clamp(30px,5.2vw,52px);font-weight:800;letter-spacing:-.03em;margin-bottom:22px}
.hero h1 em{font-style:normal;color:var(--brand)}
.lead{font-size:clamp(16px,1.9vw,18.5px);color:var(--ink-2);max-width:660px;margin:0 0 32px}
.lead strong{color:var(--ink)}
.hero-cta{display:flex;flex-wrap:wrap;gap:14px;margin-bottom:52px}
.hero-facts{
  list-style:none;padding:26px 0 0;margin:0;border-top:1px solid var(--line);
  display:grid;grid-template-columns:repeat(4,1fr);gap:24px;
}
.hero-facts b{display:block;font-size:21px;font-weight:750;letter-spacing:-.02em}
.hero-facts span{font-size:14px;color:var(--ink-3)}

/* ===== sections ===== */
.section{padding:76px 0}
.section-alt{background:var(--bg-alt);border-block:1px solid var(--line)}
.section h2{font-size:clamp(24px,3.4vw,34px);font-weight:780;letter-spacing:-.025em;margin-bottom:12px}
.sub{color:var(--ink-3);font-size:16.5px;margin:0 0 40px;max-width:640px}

/* ===== grid & cards ===== */
.grid{display:grid;gap:20px}
.grid-2{grid-template-columns:repeat(2,1fr)}
.grid-3{grid-template-columns:repeat(3,1fr)}
.card{
  background:#fff;border:1px solid var(--line);border-radius:var(--radius);
  padding:26px;box-shadow:var(--shadow);
}
.card h3{font-size:17.5px;font-weight:700;margin-bottom:9px}
.card p{margin:0;color:var(--ink-2);font-size:15.2px}
.card.plain{box-shadow:none;background:transparent;border:none;padding:0 0 8px}
.card.plain h3{color:var(--ink);font-size:19px;margin-bottom:11px}
.card.plain h3::before{content:"";display:inline-block;width:4px;height:17px;background:var(--brand);border-radius:2px;margin-right:11px;vertical-align:-2px}

/* ===== pricing ===== */
.pricing .price{display:flex;flex-direction:column;padding:30px 26px}
.tier{
  margin:0 0 10px;font-size:12.5px;font-weight:700;letter-spacing:.06em;
  text-transform:uppercase;color:var(--ink-3);
}
.price h3{font-size:22px;margin-bottom:14px}
.amount{font-size:27px;font-weight:800;letter-spacing:-.03em;color:var(--ink);margin:0 0 4px !important}
.amount small{font-size:14.5px;font-weight:500;color:var(--ink-3);letter-spacing:0}
.price .note{font-size:13.5px;color:var(--ink-3);margin:0 0 22px !important;padding-bottom:20px;border-bottom:1px solid var(--line)}
.price ul{list-style:none;padding:0;margin:0 0 26px;flex:1}
.price ul li{
  position:relative;padding-left:24px;margin-bottom:11px;
  font-size:15px;color:var(--ink-2);
}
.price ul li::before{
  content:"";position:absolute;left:4px;top:.62em;width:6px;height:6px;
  background:var(--brand);border-radius:50%;
}
.price ul li b{color:var(--ink);font-weight:650}
.price.featured{
  border-color:var(--brand);box-shadow:var(--shadow-lg);
  position:relative;
}
.price.featured .tier{color:var(--brand)}
.fineprint{
  margin:34px 0 0;padding:20px 22px;background:#fff;border:1px dashed #d5dce8;
  border-radius:12px;font-size:14.6px;color:var(--ink-3);
}

/* ===== steps ===== */
.steps{list-style:none;padding:0;margin:0;counter-reset:s}
.steps li{display:flex;gap:22px;padding-bottom:34px;position:relative}
.steps li:not(:last-child)::after{
  content:"";position:absolute;left:19px;top:44px;bottom:6px;width:2px;background:var(--line);
}
.num{
  flex-shrink:0;width:40px;height:40px;border-radius:50%;
  background:var(--brand);color:#fff;font-weight:700;font-size:17px;
  display:grid;place-items:center;position:relative;z-index:1;
}
.steps h3{font-size:18.5px;font-weight:700;margin-bottom:6px}
.steps p{margin:0;color:var(--ink-2);font-size:15.4px}

/* ===== faq ===== */
details{border-bottom:1px solid var(--line);padding:19px 0}
details summary{
  cursor:pointer;font-weight:650;font-size:16.8px;list-style:none;
  display:flex;justify-content:space-between;align-items:flex-start;gap:16px;
}
details summary::-webkit-details-marker{display:none}
details summary::after{
  content:"+";font-size:22px;font-weight:400;color:var(--brand);
  line-height:1;flex-shrink:0;transition:transform .18s;
}
details[open] summary::after{content:"−"}
details summary:hover{color:var(--brand)}
details p{margin:13px 0 2px;color:var(--ink-2);font-size:15.4px}

/* ===== contact ===== */
.contact{background:var(--bg-alt);border-top:1px solid var(--line)}
.contact-grid{display:grid;grid-template-columns:1.45fr 1fr;gap:28px;align-items:start}
form{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:28px;box-shadow:var(--shadow)}
.field{margin-bottom:19px}
.field label{display:block;font-size:14.6px;font-weight:640;margin-bottom:7px;color:var(--ink)}
.field label b{color:var(--err);font-weight:600}
.field input,.field textarea,.field select{
  width:100%;padding:11px 14px;border:1px solid #d7dde8;border-radius:9px;
  font-size:15.5px;font-family:inherit;color:var(--ink);background:#fff;
  transition:border-color .15s,box-shadow .15s;
}
.field textarea{resize:vertical;line-height:1.65;min-height:96px}
.field input:focus,.field textarea:focus,.field select:focus{
  outline:none;border-color:var(--brand);box-shadow:0 0 0 3px rgba(26,92,255,.13);
}
.field input.invalid,.field textarea.invalid{border-color:var(--err);box-shadow:0 0 0 3px rgba(192,38,38,.1)}
.form-note{font-size:13.2px;color:var(--ink-3);text-align:center;margin:13px 0 0}
.form-msg{margin:14px 0 0;font-size:15px;font-weight:600;text-align:center;display:none}
.form-msg.show{display:block}
.form-msg.ok{color:var(--ok)}
.form-msg.err{color:var(--err)}

.wechat-card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:26px;box-shadow:var(--shadow);text-align:center}
.wechat-card h3{font-size:17.5px;margin-bottom:18px}
.qr-slot{margin-bottom:16px}
.qr-slot img{width:100%;max-width:216px;height:auto;margin:0 auto;border-radius:10px;border:1px solid var(--line);background:#fff}
.qr-placeholder{
  aspect-ratio:1;max-width:210px;margin:0 auto;border:2px dashed #cfd7e5;border-radius:12px;
  display:grid;place-content:center;gap:5px;color:var(--ink-3);background:var(--bg-alt);
}
.qr-placeholder span{font-size:14.5px;font-weight:600}
.qr-placeholder small{font-size:12.5px}
.wx-id{font-size:15.2px;margin:0 0 8px;color:var(--ink-2)}
.wx-id b{color:var(--ink);font-weight:700;letter-spacing:.02em}
.wx-tip{font-size:13.4px;color:var(--ink-3);margin:0}

/* ===== footer ===== */
.footer{padding:44px 0;background:var(--ink);color:#fff;text-align:center}
.footer p{margin:0 0 6px;font-size:15.2px}
.footer .muted{color:#93a0b8;font-size:14px}
.footer .small{font-size:12.8px;margin-top:14px;color:#6c7a94}

/* ===== responsive ===== */
@media (max-width:900px){
  .nav-links{display:none}
  .grid-2,.grid-3{grid-template-columns:1fr}
  .contact-grid{grid-template-columns:1fr}
  .hero-facts{grid-template-columns:repeat(2,1fr);gap:20px}
  .hero{padding:60px 0 56px}
  .section{padding:58px 0}
  .price.featured{order:-1}
}
@media (max-width:520px){
  .wrap{padding:0 18px}
  .hero-cta .btn{width:100%}
  form,.card,.wechat-card{padding:22px 19px}
}