/* 契识官网样式 */
:root {
  --bg: #f7f7f9;
  --ink: #20202a;
  --muted: #6d6d78;
  --rose: #e85d75;
  --rose-2: #f08ba0;
  --peach: #f6c6a8;
  --card: #ffffff;
  --line: rgba(32, 32, 42, 0.08);
  --serif: "Songti SC", "Noto Serif SC", "STSong", "SimSun", serif;
  --sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue", "Microsoft YaHei", sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

img { display: block; max-width: 100%; }

a { color: inherit; text-decoration: none; }

.dot { color: var(--rose); }

/* ---------- Nav ---------- */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  transition: background .3s ease, box-shadow .3s ease;
}

.nav.scrolled {
  background: rgba(247, 247, 249, 0.86);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  box-shadow: 0 1px 0 var(--line);
}

.nav-inner {
  max-width: 1120px;
  margin: 0 auto;
  padding: 18px 24px;
  display: flex;
  align-items: center;
  gap: 32px;
}

.brand { display: flex; align-items: center; gap: 10px; }

.brand-logo {
  width: 40px; height: 40px;
  border-radius: 10px;
  object-fit: cover;
}

.brand-name {
  font-family: var(--serif);
  font-size: 22px;
  font-weight: 700;
  letter-spacing: 2px;
}

.nav-links {
  margin-left: auto;
  display: flex;
  gap: 28px;
  font-size: 14px;
  color: var(--muted);
}

.nav-links a { transition: color .2s ease; }
.nav-links a:hover { color: var(--rose); }

.nav-cta {
  padding: 8px 18px;
  border-radius: 999px;
  background: var(--ink);
  color: #fff;
  font-size: 14px;
  transition: background .2s ease, transform .2s ease;
}

.nav-cta:hover { background: var(--rose); transform: translateY(-1px); }

/* ---------- Hero ---------- */
.hero {
  max-width: 960px;
  margin: 0 auto;
  padding: 168px 24px 96px;
  text-align: center;
}

.hero-badge {
  display: inline-block;
  padding: 6px 16px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--muted);
  font-size: 13px;
  letter-spacing: 1px;
  margin-bottom: 28px;
}

.hero h1 {
  font-family: var(--serif);
  font-size: clamp(40px, 7vw, 72px);
  line-height: 1.18;
  font-weight: 700;
  letter-spacing: 1px;
}

.hero-sub {
  margin-top: 28px;
  color: var(--muted);
  font-size: clamp(15px, 2vw, 18px);
}

.hero-cta {
  margin-top: 40px;
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  padding: 14px 32px;
  border-radius: 999px;
  font-size: 15px;
  transition: transform .2s ease, box-shadow .2s ease, background .2s ease;
}

.btn-primary {
  background: linear-gradient(135deg, var(--rose) 0%, var(--rose-2) 60%, var(--peach) 100%);
  color: #fff;
  box-shadow: 0 10px 24px rgba(232, 93, 117, 0.28);
}

.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 14px 30px rgba(232, 93, 117, 0.36); }

.btn-ghost {
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink);
}

.btn-ghost:hover { transform: translateY(-2px); border-color: var(--rose); color: var(--rose); }

.hero-stats {
  margin-top: 72px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.stat strong {
  display: block;
  font-family: var(--serif);
  font-size: clamp(26px, 3.4vw, 40px);
  color: var(--rose);
  line-height: 1.2;
}

.stat span { color: var(--muted); font-size: 13px; }

/* ---------- 通用 section ---------- */
.section-label {
  color: var(--rose);
  font-size: 13px;
  letter-spacing: 3px;
  text-align: center;
  margin-bottom: 20px;
}

.section-label.light { color: rgba(255, 255, 255, 0.85); }

.section-title {
  font-family: var(--serif);
  font-size: clamp(30px, 4.6vw, 48px);
  text-align: center;
  line-height: 1.3;
}

.section-lead {
  margin-top: 16px;
  text-align: center;
  color: var(--muted);
}

/* ---------- Letter ---------- */
.letter { padding: 48px 24px 96px; }

.letter-card {
  max-width: 760px;
  margin: 0 auto;
  background: var(--card);
  border-radius: 24px;
  padding: clamp(32px, 5vw, 64px);
  box-shadow: 0 24px 60px rgba(32, 32, 42, 0.06);
}

.letter-card h2 {
  font-family: var(--serif);
  font-size: clamp(24px, 3.4vw, 34px);
  margin-bottom: 24px;
}

.letter-card p { margin-bottom: 18px; color: #3c3c46; }

.letter-sign {
  text-align: right;
  color: var(--muted);
  margin-bottom: 0;
}

/* ---------- Features ---------- */
.features { padding: 48px 24px 96px; }

.feature-list {
  max-width: 1080px;
  margin: 64px auto 0;
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.feature {
  display: grid;
  grid-template-columns: 1fr 1.1fr;
  gap: clamp(24px, 4vw, 56px);
  align-items: center;
  background: var(--card);
  border-radius: 28px;
  padding: clamp(28px, 4vw, 56px);
  box-shadow: 0 24px 60px rgba(32, 32, 42, 0.05);
}

.feature.reverse .feature-text { order: 2; }
.feature.reverse .feature-media { order: 1; }

.feature-num {
  color: var(--rose);
  font-size: 13px;
  letter-spacing: 2px;
  margin-bottom: 14px;
}

.feature-text h3 {
  font-family: var(--serif);
  font-size: clamp(22px, 3vw, 32px);
  line-height: 1.35;
  margin-bottom: 16px;
}

.feature-text p { color: var(--muted); font-size: 15px; }

.feature-tags {
  margin-top: 18px;
  font-size: 13px;
  color: var(--rose);
  letter-spacing: 1px;
}

.feature-media img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  border-radius: 20px;
  background: #fdf0f3;
}

/* ---------- Download ---------- */
.download { padding: 0 24px 112px; }

.download-inner {
  max-width: 1080px;
  margin: 0 auto;
  border-radius: 32px;
  padding: clamp(48px, 7vw, 96px) 24px;
  text-align: center;
  background: linear-gradient(150deg, var(--rose) 0%, var(--rose-2) 55%, var(--peach) 100%);
  color: #fff;
  box-shadow: 0 32px 80px rgba(232, 93, 117, 0.3);
}

.download-inner h2 {
  font-family: var(--serif);
  font-size: clamp(30px, 4.6vw, 52px);
  line-height: 1.3;
}

.download-inner .dot { color: #fff; }

.download-sub { margin-top: 16px; color: rgba(255, 255, 255, 0.9); }

.download-card {
  margin: 44px auto 0;
  max-width: 420px;
  background: #fff;
  color: var(--ink);
  border-radius: 24px;
  padding: 36px 28px;
  box-shadow: 0 20px 48px rgba(32, 32, 42, 0.16);
}

.download-logo {
  width: 96px; height: 96px;
  margin: 0 auto;
  border-radius: 22px;
  object-fit: cover;
}

.download-name {
  margin-top: 14px;
  font-family: var(--serif);
  font-size: 18px;
  font-weight: 700;
}

.download-steps {
  list-style: none;
  margin-top: 22px;
  display: flex;
  justify-content: center;
  gap: 20px;
  flex-wrap: wrap;
  color: var(--muted);
  font-size: 13px;
}

.download-steps strong {
  display: block;
  color: var(--rose);
  font-family: var(--serif);
  font-size: 16px;
}

/* ---------- Footer ---------- */
.footer {
  padding: 48px 24px 56px;
  text-align: center;
  color: var(--muted);
  font-size: 13px;
}

.footer-logo {
  width: 44px; height: 44px;
  margin: 0 auto 14px;
  border-radius: 12px;
  object-fit: cover;
  opacity: .9;
}

/* ---------- Reveal 动画 ---------- */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity .7s ease, transform .7s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- 响应式 ---------- */
@media (max-width: 860px) {
  .nav-links { display: none; }

  .hero { padding-top: 132px; }

  .hero-stats { grid-template-columns: repeat(2, 1fr); }

  .feature,
  .feature.reverse {
    grid-template-columns: 1fr;
  }

  .feature.reverse .feature-text { order: 1; }
  .feature.reverse .feature-media { order: 2; }
}