:root {
  --primary: #2563eb;
  --primary-2: #3b82f6;
  --primary-deep: #1d4ed8;
  --ink: #0f172a;
  --ink-2: #475569;
  --ink-3: #94a3b8;
  --bg: #ffffff;
  --bg-soft: #f6f8fc;
  --line: #e8edf5;
  --ok: #16a34a;
  --err: #dc2626;
  --radius: 14px;
  --shadow: 0 8px 30px rgba(15, 23, 42, .08);
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font: 15px/1.7 -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
        "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--ink);
  background: var(--bg);
}
a { color: var(--primary); text-decoration: none; }
a:hover { color: var(--primary-deep); }
img { max-width: 100%; }

.wrap { max-width: 1120px; margin: 0 auto; padding: 0 24px; }

/* ---------- 顶栏 ---------- */
.topbar {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, .9);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.topbar-inner { display: flex; align-items: center; height: 64px; gap: 28px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 18px; color: var(--ink); }
.brand:hover { color: var(--ink); }
.brand .mark { width: 30px; height: 30px; flex: 0 0 auto; }
.nav { display: flex; gap: 24px; margin-left: 8px; }
.nav a { color: var(--ink-2); font-size: 14.5px; font-weight: 500; }
.nav a:hover { color: var(--primary); }
.topbar-spacer { flex: 1; }
.topbar .acct { display: flex; align-items: center; gap: 14px; }
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 10px 18px; border-radius: 10px; border: 1px solid transparent;
  font-size: 14.5px; font-weight: 600; cursor: pointer; line-height: 1.2;
  transition: .18s; text-decoration: none;
}
.btn.primary {
  background: linear-gradient(135deg, var(--primary-2), var(--primary));
  color: #fff; box-shadow: 0 6px 18px rgba(37, 99, 235, .28);
}
.btn.primary:hover { color: #fff; filter: brightness(1.06); transform: translateY(-1px); }
.btn.ghost { background: #fff; color: var(--ink); border-color: var(--line); }
.btn.ghost:hover { border-color: var(--primary); color: var(--primary); }
.btn.block { width: 100%; }
.btn.lg { padding: 13px 26px; font-size: 15.5px; border-radius: 12px; }

/* ---------- Hero ---------- */
.hero { padding: 72px 0 64px; text-align: center;
  background: radial-gradient(1200px 500px at 50% -10%, #e8f0ff 0%, #ffffff 60%); }
.hero .tag { display: inline-block; padding: 6px 14px; border-radius: 999px;
  background: #eef4ff; color: var(--primary); font-size: 13px; font-weight: 600; }
.hero h1 { font-size: 44px; line-height: 1.2; margin: 18px 0 14px; letter-spacing: -.5px; }
.hero h1 .grad { background: linear-gradient(135deg, var(--primary-2), var(--primary-deep));
  -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero p.sub { color: var(--ink-2); font-size: 17px; max-width: 640px; margin: 0 auto 28px; }
.hero .cta { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.hero .stat { display: flex; gap: 40px; justify-content: center; margin-top: 40px; flex-wrap: wrap; }
.hero .stat div { text-align: center; }
.hero .stat b { display: block; font-size: 24px; color: var(--ink); }
.hero .stat span { color: var(--ink-3); font-size: 13px; }

/* ---------- 通用区块 ---------- */
.section { padding: 64px 0; }
.section.soft { background: var(--bg-soft); }
.section-head { text-align: center; margin-bottom: 40px; }
.section-head h2 { font-size: 30px; margin: 0 0 10px; letter-spacing: -.3px; }
.section-head p { color: var(--ink-2); margin: 0; }

/* ---------- 特性 ---------- */
.features { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.feature { background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 26px 22px; box-shadow: var(--shadow); }
.feature .ico { width: 44px; height: 44px; border-radius: 12px; display: flex; align-items: center;
  justify-content: center; font-size: 22px; background: #eef4ff; margin-bottom: 14px; }
.feature h3 { font-size: 16px; margin: 0 0 8px; }
.feature p { color: var(--ink-2); font-size: 13.5px; margin: 0; }

/* ---------- 套餐 ---------- */
.plans { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.plan { background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 28px 24px; display: flex; flex-direction: column; box-shadow: var(--shadow); position: relative; }
.plan.hot { border-color: var(--primary); box-shadow: 0 12px 34px rgba(37, 99, 235, .16); }
.plan .hot-tag { position: absolute; top: -12px; left: 24px; background: linear-gradient(135deg, var(--primary-2), var(--primary));
  color: #fff; font-size: 12px; font-weight: 700; padding: 3px 12px; border-radius: 999px; }
.plan h3 { font-size: 17px; margin: 0 0 4px; }
.plan .desc { color: var(--ink-3); font-size: 13px; margin-bottom: 18px; }
.plan .price { font-size: 34px; font-weight: 800; color: var(--ink); }
.plan .price small { font-size: 15px; font-weight: 600; color: var(--ink-2); }
.plan .meta { margin: 18px 0; border-top: 1px solid var(--line); padding-top: 16px; }
.plan .meta div { display: flex; justify-content: space-between; font-size: 14px; color: var(--ink-2); padding: 5px 0; }
.plan .meta b { color: var(--ink); }
.plan .buy { margin-top: auto; }

/* ---------- 平台下载 ---------- */
.platforms { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.platform { text-align: center; padding: 26px 16px; border: 1px solid var(--line); border-radius: var(--radius); background: #fff; }
.platform .ico { font-size: 30px; margin-bottom: 10px; }
.platform h4 { margin: 0 0 4px; font-size: 15px; }
.platform span { color: var(--ink-3); font-size: 12.5px; display: block; margin-bottom: 14px; }

/* ---------- 帮助 ---------- */
.faq-cat { margin-bottom: 28px; }
.faq-cat h3 { font-size: 18px; margin: 0 0 12px; padding-left: 12px; border-left: 3px solid var(--primary); }
.faq { border: 1px solid var(--line); border-radius: var(--radius); background: #fff; overflow: hidden; }
.faq details { border-bottom: 1px solid var(--line); }
.faq details:last-child { border-bottom: 0; }
.faq summary { cursor: pointer; padding: 16px 20px; font-weight: 600; list-style: none;
  position: relative; user-select: none; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; position: absolute; right: 20px; color: var(--ink-3); font-size: 20px; }
.faq details[open] summary::after { content: "−"; }
.faq .body { padding: 0 20px 16px; color: var(--ink-2); }

/* ---------- 表单（登录/注册/找回） ---------- */
.auth { max-width: 420px; margin: 40px auto; }
.auth .card { background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 32px 28px; box-shadow: var(--shadow); }
.auth h1 { font-size: 22px; margin: 0 0 6px; }
.auth .sub { color: var(--ink-3); font-size: 14px; margin: 0 0 22px; }
.field { margin-bottom: 16px; }
.field label { display: block; font-size: 13.5px; font-weight: 600; color: var(--ink-2); margin-bottom: 6px; }
.field input { width: 100%; padding: 11px 13px; border: 1px solid var(--line); border-radius: 10px;
  font-size: 15px; color: var(--ink); background: #fff; outline: none; transition: .15s; }
.field input:focus { border-color: var(--primary); box-shadow: 0 0 0 3px rgba(37, 99, 235, .12); }
.field .cap-row { display: flex; gap: 10px; }
.field .cap-row input { flex: 1; }
.field .cap-row img { width: 108px; height: 42px; border-radius: 10px; cursor: pointer; border: 1px solid var(--line); }
.field .code-row { display: flex; gap: 10px; }
.field .code-row input { flex: 1; }
.field .code-row button { flex: 0 0 auto; white-space: nowrap; }
.msg { border-radius: 10px; padding: 11px 14px; font-size: 13.5px; margin-bottom: 16px; }
.msg.err { background: #fef2f2; color: var(--err); border: 1px solid #fecaca; }
.msg.ok { background: #f0fdf4; color: var(--ok); border: 1px solid #bbf7d0; }
.auth .foot { margin-top: 18px; text-align: center; font-size: 14px; color: var(--ink-2); }
.link { color: var(--primary); cursor: pointer; font-weight: 600; }

/* ---------- 支付结果 ---------- */
.pay-result { text-align: center; padding: 56px 0; }
.pay-result .ico { font-size: 56px; margin-bottom: 16px; }
.pay-result h2 { margin: 0 0 10px; }
.pay-result p { color: var(--ink-2); margin: 0 0 26px; }

/* ---------- 页脚 ---------- */
.footer { border-top: 1px solid var(--line); padding: 32px 0; color: var(--ink-3); font-size: 13.5px; }
.footer .wrap { display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; }

@media (max-width: 860px) {
  .features, .plans, .platforms { grid-template-columns: repeat(2, 1fr); }
  .hero h1 { font-size: 32px; }
  .nav { display: none; }
}
@media (max-width: 520px) {
  .features, .plans, .platforms { grid-template-columns: 1fr; }
}