* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
  color: #1f2329;
  background: #ffffff;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

a { color: #d97706; text-decoration: none; }
a:hover { color: #ff8a00; }

img { max-width: 100%; }

.wrap {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 24px;
}

header.site {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.96);
  border-bottom: 1px solid #eceff3;
  backdrop-filter: blur(8px);
}

.nav {
  display: flex;
  align-items: center;
  gap: 36px;
  height: 68px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 18px;
  font-weight: 700;
  color: #1f2329;
  flex-shrink: 0;
}

.brand img {
  width: 34px;
  height: 34px;
  border-radius: 9px;
}

.nav ul {
  display: flex;
  gap: 28px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-size: 15px;
  flex: 1;
}

.nav ul a { color: #3c444e; }
.nav ul a:hover, .nav ul a.active { color: #ff8a00; }

.btn {
  display: inline-block;
  padding: 11px 28px;
  border-radius: 999px;
  background: linear-gradient(135deg, #ffb01f, #ff8a00);
  color: #ffffff;
  font-size: 15px;
  font-weight: 600;
  box-shadow: 0 6px 16px rgba(255, 154, 0, 0.26);
  white-space: nowrap;
}

.btn:hover { color: #ffffff; }
.btn:active { transform: scale(0.97); }

.btn.big {
  padding: 15px 54px;
  font-size: 17px;
}

.hero {
  padding: 68px 0 60px;
  background: linear-gradient(180deg, #fff8e8 0%, #ffffff 100%);
  text-align: center;
}

.hero .app-icon {
  width: 92px;
  height: 92px;
  border-radius: 22px;
  box-shadow: 0 12px 28px rgba(255, 154, 0, 0.22);
}

.hero h1 {
  margin: 22px 0 12px;
  font-size: 40px;
  letter-spacing: 2px;
}

.hero .lead {
  margin: 0 auto;
  max-width: 620px;
  font-size: 19px;
  color: #3c444e;
}

.hero .desc {
  margin: 16px auto 0;
  max-width: 660px;
  font-size: 15px;
  color: #6b737d;
}

.hero .btn.big { margin-top: 34px; }

.hero .meta {
  margin: 16px 0 0;
  font-size: 13px;
  color: #9aa1a9;
}

.section { padding: 64px 0; }
.section.alt { background: #fafbfc; border-top: 1px solid #f1f3f6; border-bottom: 1px solid #f1f3f6; }

.section h2 {
  margin: 0 0 10px;
  font-size: 27px;
  text-align: center;
}

.section .subtitle {
  margin: 0 auto 44px;
  max-width: 640px;
  text-align: center;
  color: #7a828c;
  font-size: 15px;
}

.grid3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.grid2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.card {
  background: #ffffff;
  border: 1px solid #eceff3;
  border-radius: 16px;
  padding: 30px 26px;
}

.section.alt .card { border-color: #e8ebef; }

.card h3 {
  margin: 0 0 12px;
  font-size: 18px;
}

.card p {
  margin: 0;
  color: #5c646e;
  font-size: 15px;
}

.card .step {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 30px;
  margin-bottom: 14px;
  border-radius: 50%;
  background: #fff4e0;
  color: #e08200;
  font-weight: 700;
  font-size: 15px;
}

.topic img {
  display: block;
  width: 100%;
  border-radius: 14px;
  border: 1px solid #eceff3;
}

.topic h3 {
  margin: 16px 0 6px;
  font-size: 17px;
}

.topic p {
  margin: 0;
  color: #5c646e;
  font-size: 14px;
}

.page-head {
  padding: 56px 0 40px;
  background: linear-gradient(180deg, #fff8e8 0%, #ffffff 100%);
  border-bottom: 1px solid #f1f3f6;
}

.page-head h1 {
  margin: 0 0 10px;
  font-size: 32px;
}

.page-head p {
  margin: 0;
  max-width: 700px;
  color: #6b737d;
  font-size: 15px;
}

.crumb {
  margin: 0 0 14px;
  font-size: 13px;
  color: #9aa1a9;
}

.prose p {
  margin: 0 0 18px;
  font-size: 15.5px;
  color: #3c444e;
}

.prose h2 {
  margin: 40px 0 16px;
  font-size: 22px;
  text-align: left;
}

.prose h3 {
  margin: 28px 0 10px;
  font-size: 17px;
}

.facts {
  width: 100%;
  border-collapse: collapse;
  font-size: 15px;
}

.facts th, .facts td {
  padding: 13px 16px;
  border: 1px solid #eceff3;
  text-align: left;
}

.facts th {
  width: 190px;
  background: #fafbfc;
  color: #5c646e;
  font-weight: 500;
}

.mail-box {
  text-align: center;
  padding: 44px 24px;
  border: 1px solid #eceff3;
  border-radius: 18px;
  background: #fffdf7;
}

.mail-box .mail {
  display: inline-block;
  margin-top: 8px;
  font-size: 25px;
  font-weight: 700;
  color: #d97706;
  letter-spacing: 0.5px;
}

.mail-box .note {
  margin: 14px 0 0;
  color: #7a828c;
  font-size: 14px;
}

dl.faq { margin: 0; }

dl.faq dt {
  margin-top: 26px;
  font-weight: 600;
  font-size: 16px;
}

dl.faq dd {
  margin: 8px 0 0;
  color: #5c646e;
  font-size: 15px;
}

footer.site {
  margin-top: 8px;
  padding: 46px 0 34px;
  background: #1f2329;
  color: #9aa1a9;
  font-size: 13.5px;
}

footer.site a { color: #c8cdd4; }
footer.site a:hover { color: #ffffff; }

.foot-top {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 28px;
  padding-bottom: 26px;
  border-bottom: 1px solid #31373e;
}

.foot-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
  color: #ffffff;
  font-size: 16px;
  font-weight: 600;
}

.foot-brand img {
  width: 30px;
  height: 30px;
  border-radius: 8px;
}

.foot-col p { margin: 0 0 6px; }

.foot-links {
  display: flex;
  gap: 22px;
}

.foot-bottom {
  padding-top: 22px;
  line-height: 2;
}

@media (max-width: 860px) {
  /* 小屏没有空间放横向导航，改为「品牌+下载」一行、导航链接另起一行，避免手机访问时进不去子页面 */
  .nav {
    flex-wrap: wrap;
    height: auto;
    padding: 12px 0;
    gap: 12px;
  }
  /* 基线 ul 是 flex:1（flex-basis 为 0），只写 width:100% 不参与主轴尺寸计算，必须用 flex-basis 才能让它独占一行 */
  .nav ul {
    order: 3;
    flex: 1 0 100%;
    gap: 20px;
    font-size: 14px;
    overflow-x: auto;
  }
  .nav ul a {
    white-space: nowrap;
  }
  .nav .btn {
    margin-left: auto;
    padding: 9px 20px;
    font-size: 14px;
  }
  .grid3, .grid2 { grid-template-columns: 1fr; }
  .hero h1 { font-size: 32px; }
  .hero .lead { font-size: 17px; }
  .facts th { width: 120px; }
  .foot-top { flex-direction: column; }
}