/* ===== 基础重置 ===== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  line-height: 1.6;
  color: #333;
  background: #f9f9f9;
}

.container {
  width: 90%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 15px;
}

/* ===== 导航栏 ===== */
.navbar {
  background: #ffffff;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  position: sticky;
  top: 0;
  z-index: 100;
}

.navbar .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 15px;
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: #333;
}

.nav-links {
  list-style: none;
  display: flex;
  gap: 2rem;
}

.nav-links a {
  text-decoration: none;
  color: #555;
  font-weight: 500;
  transition: color 0.3s;
}

.nav-links a:hover,
.nav-links a.active {
  color: #007bff;
}

.menu-toggle {
  display: none;  /* 桌面端隐藏 */
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 5px;
}

.menu-toggle span {
  display: block;
  width: 28px;
  height: 3px;
  background: #333;
  border-radius: 3px;
  transition: 0.3s;
}

/* ===== 首页 Hero ===== */
.hero {
  background: linear-gradient(135deg, #007bff, #6610f2);
  color: white;
  text-align: center;
  padding: 100px 0;
}

.hero h1 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

.hero p {
  font-size: 1.2rem;
  margin-bottom: 2rem;
  opacity: 0.9;
}

.btn {
  display: inline-block;
  background: white;
  color: #007bff;
  padding: 12px 30px;
  border-radius: 30px;
  text-decoration: none;
  font-weight: 600;
  transition: transform 0.3s, box-shadow 0.3s;
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
}

/* ===== 功能区域 ===== */
.features {
  padding: 80px 0;
  text-align: center;
}

.features h2 {
  font-size: 2rem;
  margin-bottom: 3rem;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 30px;
}

.card {
  background: white;
  border-radius: 12px;
  padding: 30px 20px;
  box-shadow: 0 5px 20px rgba(0, 0, 0, 0.05);
  transition: transform 0.3s, box-shadow 0.3s;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.card-icon {
  font-size: 3rem;
  margin-bottom: 1rem;
}

/* ===== 关于区域 ===== */
.about {
  background: white;
  padding: 80px 0;
  text-align: center;
}

/* ===== 页脚 ===== */
.footer {
  background: #333;
  color: white;
  text-align: center;
  padding: 20px 0;
}

/* ===== 响应式：手机端 ===== */
@media (max-width: 768px) {
  .navbar .container {
    flex-wrap: wrap;
  }

  .nav-links {
    display: none;
    flex-direction: column;
    width: 100%;
    background: white;
    text-align: center;
    gap: 0;
    padding: 1rem 0;
    box-shadow: 0 5px 10px rgba(0,0,0,0.1);
    border-radius: 0 0 10px 10px;
  }

  .nav-links.show {
    display: flex;
  }

  .nav-links li {
    padding: 10px 0;
    border-bottom: 1px solid #eee;
  }

  .menu-toggle {
    display: flex;   /* 手机端显示 */
  }

  .hero h1 {
    font-size: 1.8rem;
  }

  .feature-grid {
    grid-template-columns: 1fr;  /* 单列 */
  }

  .hero {
    padding: 60px 0;
  }
}