/* 1. 全局重置 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

/* 2. 页面基础样式（所有页面共用） */
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background-color: #F8FAFC;
  color: #1F2937;
  line-height: 1.7;
}

/* 3. 导航栏（所有页面共用） */
.header {
  background-color: #0F172A;
  padding: 16px 24px;
  position: sticky;
  top: 0;
  z-index: 999;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

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

.lab-logo {
  color: #ffffff;
  text-decoration: none;
  font-size: 24px;
  font-weight: 700;
  letter-spacing: 1px;
}

.nav {
  display: flex;
  gap: 32px;
}

.nav a {
  color: rgba(255, 255, 255, 0.9);
  text-decoration: none;
  font-size: 17px;
  font-weight: 500;
  transition: all 0.2s ease;
}

.nav a:hover,
.nav a.active {
  color: #ffffff;
  border-bottom: 2px solid #3B82F6;
}

/* 4. 主容器与卡片（所有页面共用） */
.container {
  max-width: 1200px;
  margin: 48px auto;
  padding: 0 24px;
}

.card {
  background-color: #ffffff;
  border-radius: 16px;
  padding: 48px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
}

/* 5. 页脚（所有页面共用） */
.footer {
  background-color: #0F172A;
  color: rgba(255, 255, 255, 0.8);
  text-align: center;
  padding: 32px 24px;
  margin-top: 48px;
}

.footer p {
  font-size: 16px;
  line-height: 1.8;
}

.footer strong {
  color: #ffffff;
}

/* 6. 公共响应式适配（仅导航、容器、页脚） */
@media (max-width: 768px) {
  .lab-logo { font-size: 24px; }
  .nav { gap: 20px; }
  .nav a { font-size: 15px; }
  .container { margin: 32px auto; padding: 0 20px; }
  .card { padding: 32px; }
}

@media (max-width: 480px) {
  .header { padding: 12px 16px; }
  .nav-wrap {
    flex-direction: column;
    gap: 12px;
    align-items: center;
  }
  .nav { justify-content: center; flex-wrap: wrap; gap: 16px; }
  .card { padding: 24px; }
  .footer p { font-size: 14px; }
}