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

:root {
  --primary: #0d9488;
  --primary-dark: #0f766e;
  --accent: #f59e0b;
  --accent-dark: #d97706;
  --bg: #f8fafc;
  --surface: #ffffff;
  --text: #1e293b;
  --text-light: #64748b;
  --radius: 12px;
  --shadow: 0 4px 24px rgba(0,0,0,.06);
}

html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
}

/* Nav */
.nav {
  display: flex;
  align-items: center;
  gap: 24px;
  padding: 16px 32px;
  position: absolute;
  top: 0; left: 0; right: 0;
  z-index: 10;
}
.logo {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--primary);
}
.nav-link {
  color: rgba(255,255,255,.85);
  text-decoration: none;
  font-size: .9rem;
  transition: color .2s;
}
.nav-link:hover { color: #fff; }

/* Hero */
.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: #fff;
}
.hero-body {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 0 24px;
}
.hero-title {
  font-size: clamp(2.8rem, 8vw, 5rem);
  font-weight: 900;
  letter-spacing: -.02em;
  margin-bottom: 12px;
}
.hero-slogan {
  font-size: clamp(1rem, 2.5vw, 1.35rem);
  opacity: .9;
  margin-bottom: 32px;
  max-width: 480px;
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 14px 36px;
  border: none;
  border-radius: var(--radius);
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  transition: transform .2s, box-shadow .2s;
  text-decoration: none;
}
.btn:hover { transform: translateY(-2px); }
.btn:active { transform: translateY(0); }
.btn-primary {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 4px 16px rgba(245,158,11,.35);
}
.btn-accent {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 4px 16px rgba(13,148,136,.35);
}

/* Features */
.features {
  padding: 80px 24px;
  max-width: 960px;
  margin: 0 auto;
}
.section-title {
  text-align: center;
  font-size: 2rem;
  margin-bottom: 48px;
  font-weight: 800;
}
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 28px;
}
.card {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 32px 24px;
  box-shadow: var(--shadow);
  text-align: center;
  transition: transform .25s;
}
.card:hover { transform: translateY(-6px); }
.card-icon {
  font-size: 2.6rem;
  margin-bottom: 16px;
}
.card-title {
  font-size: 1.15rem;
  margin-bottom: 10px;
  color: var(--primary-dark);
}
.card-desc {
  font-size: .92rem;
  color: var(--text-light);
  line-height: 1.7;
}

/* Contact */
.contact {
  padding: 80px 24px;
  text-align: center;
  background: var(--surface);
}
.contact-desc {
  color: var(--text-light);
  margin-bottom: 28px;
  max-width: 420px;
  margin-left: auto;
  margin-right: auto;
}
.toast {
  display: none;
  margin-top: 20px;
  padding: 12px 24px;
  background: var(--primary);
  color: #fff;
  border-radius: var(--radius);
  font-size: .9rem;
  opacity: 0;
  transition: opacity .3s;
}
.toast.show { display: inline-block; opacity: 1; }

/* Footer */
.footer {
  text-align: center;
  padding: 24px;
  font-size: .82rem;
  color: var(--text-light);
}

/* Responsive */
@media (max-width: 600px) {
  .nav { padding: 12px 16px; }
  .hero-body { padding: 0 16px; }
  .features { padding: 56px 16px; }
}