/* 重置默认样式 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(135deg, #f5f7fa 0%, #e4edf9 100%);
  color: #333;
  line-height: 1.6;
  padding-top: 80px;
  min-height: 100vh;
}

/* 顶部导航栏 */
.navbar {
  background: linear-gradient(90deg, #2c3e50 0%, #1a2530 100%);
  color: white;
  padding: 1rem 0;
  position: fixed;
  top: 0;
  width: 100%;
  z-index: 1000;
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
  transition: all 0.3s ease;
}

.navbar.scrolled {
  padding: 0.5rem 0;
  box-shadow: 0 2px 8px rgba(0,0,0,0.2);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo h2 {
  color: #3498db;
  margin: 0;
  font-size: 1.8rem;
  background: linear-gradient(90deg, #3498db, #2c3e50);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  transition: all 0.3s ease;
}

.logo h2:hover {
  transform: scale(1.05);
}

.nav-menu ul {
  display: flex;
  list-style: none;
}

.nav-menu ul li {
  margin-left: 1.5rem;
}

.nav-menu ul li a {
  color: #ecf0f1;
  text-decoration: none;
  font-weight: 500;
  transition: all 0.3s ease;
  padding: 0.5rem 1rem;
  border-radius: 30px;
  position: relative;
  overflow: hidden;
}

.nav-menu ul li a:hover {
  color: #3498db;
  background-color: rgba(255, 255, 255, 0.1);
  transform: translateY(-2px);
}

.nav-menu ul li a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  width: 0;
  height: 2px;
  background-color: #3498db;
  transition: all 0.3s ease;
  transform: translateX(-50%);
}

.nav-menu ul li a:hover::after {
  width: 70%;
}

/* 主要内容区域 */
.main-content {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem 20px;
  animation: fadeIn 0.8s ease-out;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

/* 卡片样式 */
.card {
  background: linear-gradient(135deg, #ffffff 0%, #f8f9fa 100%);
  border-radius: 15px;
  padding: 2rem;
  box-shadow: 0 8px 20px rgba(0,0,0,0.08);
  transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  border: 1px solid rgba(255,255,255,0.5);
  backdrop-filter: blur(10px);
  margin-bottom: 2rem;
}

.card:hover {
  transform: translateY(-10px) scale(1.02);
  box-shadow: 0 15px 35px rgba(0,0,0,0.15);
}

.card h3 {
  color: #2c3e50;
  margin-bottom: 1rem;
  font-size: 1.5rem;
  position: relative;
  padding-bottom: 0.5rem;
}

.card h3::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 50px;
  height: 3px;
  background: linear-gradient(90deg, #3498db, #2c3e50);
  border-radius: 3px;
}

.card p {
  color: #7f8c8d;
  margin-bottom: 1.5rem;
  font-size: 1.1rem;
}

/* 按钮样式 */
.btn {
  display: inline-block;
  padding: 12px 30px;
  border-radius: 30px;
  text-decoration: none;
  font-weight: 600;
  transition: all 0.3s ease;
  border: none;
  cursor: pointer;
  font-size: 1rem;
  position: relative;
  overflow: hidden;
  z-index: 1;
}

.btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 0;
  height: 100%;
  background: rgba(255,255,255,0.2);
  transition: all 0.5s ease;
  z-index: -1;
}

.btn:hover::before {
  width: 100%;
}

.primary-btn {
  background: linear-gradient(90deg, #3498db, #2c3e50);
  color: white;
  box-shadow: 0 4px 15px rgba(52, 152, 219, 0.3);
}

.primary-btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 20px rgba(52, 152, 219, 0.4);
}

.secondary-btn {
  background: transparent;
  color: #3498db;
  border: 2px solid #3498db;
}

.secondary-btn:hover {
  background-color: rgba(52, 152, 219, 0.1);
  transform: translateY(-3px);
}

/* 页脚 */
.footer {
  background: linear-gradient(90deg, #2c3e50 0%, #1a2530 100%);
  color: white;
  text-align: center;
  padding: 3rem 2rem;
  margin-top: 3rem;
  position: relative;
}

.footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: linear-gradient(90deg, #3498db, #2c3e50);
}

.footer p {
  margin: 0;
  font-size: 1.1rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
  .nav-container {
    flex-direction: column;
    gap: 1rem;
  }
  
  .nav-menu ul {
    flex-wrap: wrap;
    justify-content: center;
  }
  
  .nav-menu ul li {
    margin: 0.5rem;
  }
  
  .main-content {
    padding: 1.5rem 15px;
  }
  
  .card {
    padding: 1.5rem;
  }
  
  .logo h2 {
    font-size: 1.5rem;
  }
}

@media (max-width: 480px) {
  body {
    padding-top: 70px;
  }
  
  .main-content {
    padding: 1rem 10px;
  }
  
  .card {
    padding: 1.2rem;
  }
  
  .card h3 {
    font-size: 1.3rem;
  }
  
  .btn {
    padding: 10px 20px;
    font-size: 0.9rem;
  }
}