:root {
  --primary: #2e8b57; /* 环保绿色 */
  --secondary: #1976d2; /* 科技蓝 */
}

html, body {
  height: 100%;
}

body {
  font-family: Roboto, "Microsoft YaHei", -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Arial, "Noto Sans", "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", sans-serif;
  margin: 0;
  background-color: #f4f7f9;
  color: #333;
}

.page-title {
  font-family: Montserrat, Roboto, sans-serif;
  font-weight: 700;
  letter-spacing: .5px;
}

.navbar.bg-primary {
  background: linear-gradient(90deg, var(--primary), var(--secondary));
}

.hero-section {
  min-height: 52vh;
  background: linear-gradient(rgba(30, 60, 30, .55), rgba(20, 40, 80, .55)), url('../images/hero-industrial.svg') center/cover no-repeat;
}

/* 卡片与布局 */
.card-title {
  font-weight: 600;
}

footer .footer-links a {
  text-decoration: none;
}

/* 响应式微调 */
@media (max-width: 768px) {
  .hero-section .display-5 {
    font-size: 2rem;
  }
}

/* 表格优化 */
table.table th, table.table td {
  vertical-align: middle;
}

/* 可访问性与焦点状态 */
a:focus, button:focus, input:focus, textarea:focus {
  outline: 2px solid #80deea;
  outline-offset: 2px;
}