* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Microsoft YaHei", sans-serif;
}

:root {
  --primary: #165DFF;
  --dark: #111827;
  --light: #f9fafb;
  --gray: #6b7280;
}

body {
  background: #fff;
  color: var(--dark);
  line-height: 1.6;
}

header {
  background: white;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.08);
  position: sticky;
  top: 0;
  z-index: 999;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

.nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  min-height: 70px;
}

.logo {
  font-size: 22px;
  font-weight: bold;
  color: var(--primary);
  display: flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: 30px;
}

.nav-menu a {
  text-decoration: none;
  color: var(--dark);
  font-weight: 500;
  transition: 0.3s;
}

.nav-menu a:hover,
.nav-menu a.active {
  color: var(--primary);
}

.hero {
  background: linear-gradient(135deg, #165DFF 0%, #0B3B9A 100%);
  color: white;
  padding: 100px 0;
  text-align: center;
}

.hero h1 {
  font-size: 42px;
  margin-bottom: 20px;
}

.hero p {
  font-size: 18px;
  max-width: 700px;
  margin: 0 auto 40px;
  opacity: 0.95;
}

.page-hero {
  padding: 80px 0;
}

.btn {
  display: inline-block;
  padding: 14px 32px;
  background: white;
  color: var(--primary);
  border-radius: 8px;
  font-weight: bold;
  text-decoration: none;
  transition: 0.3s;
  font-size: 16px;
  border: none;
  cursor: pointer;
}

.btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.15);
}

.btn-primary {
  background: var(--primary);
  color: white;
}

.btn-outline {
  background: transparent;
  color: white;
  border: 1px solid rgba(255, 255, 255, 0.75);
}

.btn-row {
  display: flex;
  justify-content: center;
  gap: 15px;
  flex-wrap: wrap;
}

.section {
  padding: 80px 0;
}

.section-light {
  background: var(--light);
}

.title {
  text-align: center;
  font-size: 32px;
  margin-bottom: 50px;
  color: var(--dark);
}

.features,
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 30px;
}

.card {
  background: white;
  padding: 35px 25px;
  border-radius: 12px;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
  text-align: center;
  transition: 0.3s;
}

.card:hover {
  transform: translateY(-5px);
}

.card i {
  font-size: 40px;
  color: var(--primary);
  margin-bottom: 20px;
}

.card h3 {
  margin-bottom: 12px;
  font-size: 20px;
}

.card p {
  color: var(--gray);
}

.download-area {
  background: var(--light);
}

.download-box {
  max-width: 760px;
  margin: 0 auto;
  background: white;
  padding: 40px;
  border-radius: 12px;
  box-shadow: 0 5px 20px rgba(0, 0, 0, 0.06);
  text-align: center;
}

.download-box h3 {
  font-size: 24px;
  margin-bottom: 15px;
}

.download-box p {
  color: var(--gray);
  margin-bottom: 30px;
}

.meta {
  color: #999;
}

.agreement,
.content-panel {
  max-width: 900px;
  margin: 0 auto;
  line-height: 1.8;
  color: #333;
}

.content-panel {
  background: white;
  padding: 40px;
  border-radius: 12px;
  box-shadow: 0 5px 20px rgba(0, 0, 0, 0.06);
}

.content-panel h2,
.content-panel h3 {
  color: var(--dark);
  margin-bottom: 16px;
}

.content-panel h3 {
  margin-top: 30px;
  font-size: 22px;
}

.content-panel p,
.content-panel li {
  color: #333;
}

.content-panel ul,
.content-panel ol {
  padding-left: 24px;
}

.content-panel li + li {
  margin-top: 10px;
}

.steps {
  max-width: 900px;
  margin: 0 auto;
  display: grid;
  gap: 18px;
}

.step {
  display: flex;
  gap: 18px;
  align-items: flex-start;
  background: white;
  padding: 24px;
  border-radius: 12px;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
}

.step-num {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: var(--primary);
  color: white;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 auto;
  font-weight: bold;
}

.step h3 {
  margin-bottom: 6px;
}

.step p {
  color: var(--gray);
}

.notice {
  max-width: 900px;
  margin: 30px auto 0;
  padding: 20px 24px;
  border-left: 4px solid var(--primary);
  background: #eef4ff;
  color: #1f2937;
}

.error-code {
  font-size: 72px;
  line-height: 1;
  font-weight: bold;
  margin-bottom: 18px;
}

footer {
  background: var(--dark);
  color: white;
  text-align: center;
  padding: 40px 0;
}

footer p {
  opacity: 0.7;
}

@media (max-width: 768px) {
  .nav {
    align-items: flex-start;
    flex-direction: column;
    gap: 14px;
    padding: 16px 0;
  }

  .nav-menu {
    width: 100%;
    gap: 14px;
    flex-wrap: wrap;
  }

  .hero {
    padding: 72px 0;
  }

  .hero h1 {
    font-size: 28px;
  }

  .hero p {
    font-size: 16px;
  }

  .title {
    font-size: 26px;
  }

  .download-box,
  .content-panel {
    padding: 28px 20px;
  }
}