/* 全局增强样式 */
body {
  font-size: 16px;
}

.site-nav {
  box-shadow: 0 2px 8px rgba(0,0,0,0.05);
}

.nav-menu li a {
  transition: all 0.3s;
  position: relative;
}

.nav-menu li a:hover {
  color: #2563eb;
}

.nav-menu li a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 0;
  height: 2px;
  background: #2563eb;
  transition: width 0.3s;
}

.nav-menu li a:hover::after {
  width: 80%;
}

.hero {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  animation: gradientShift 10s ease infinite;
  background-size: 200% 200%;
}

@keyframes gradientShift {
  0%, 100% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
}

.card,
.list-item,
.detail-card {
  transition: all 0.3s ease;
}

.card:hover,
.list-item:hover {
  border-color: #2563eb;
}

.link-btn {
  box-shadow: 0 2px 4px rgba(37, 99, 235, 0.2);
}

.link-btn:hover {
  box-shadow: 0 4px 8px rgba(37, 99, 235, 0.3);
}

/* 移动端优化 */
@media (max-width: 768px) {
  .nav-container {
    padding: 0 0.5rem;
  }

  .nav-menu {
    flex: 1;
    justify-content: space-around;
  }

  .nav-menu li {
    flex: 1;
    min-width: 0;
  }

  .nav-menu li a {
    overflow: hidden;
    text-overflow: ellipsis;
    padding: 1rem 0.3rem;
  }
}

/* 返回顶部按钮 */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 48px;
  height: 48px;
  background: #2563eb;
  color: #fff;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.back-to-top.show {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  background: #1d4ed8;
  transform: translateY(-4px);
}