/* Reset & Base */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
  line-height: 1.6;
  color: #333;
  background-color: #f9f9f9;
}
/* 确保 html 和 body 占满全高 */
html, body {
  min-height: 100%;
}

/* 页面主容器：使用 flex 布局，垂直方向，最小高度 100vh */
.page-wrapper {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* main 区域自动撑开，把 footer 推到底部 */
.page-wrapper > main {
  flex: 1;
}

/* 其他原有样式保持不变... */
a {
  text-decoration: none;
  color: inherit;
}

ul {
  list-style: none;
}

/* Header & Navigation */
header {
  background: #2c3e50;
  color: white;
  padding: 1rem 2rem;
}

nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: bold;
}

nav ul {
  display: flex;
  gap: 1.5rem;
}

nav a {
  padding: 0.5rem 1rem;
  border-radius: 4px;
  transition: background 0.3s;
}

nav a.active,
nav a:hover {
  background: #34495e;
}

/* Main Content */
main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem;
}

.hero {
  text-align: center;
  padding: 4rem 2rem;
  background: #ecf0f1;
  margin-bottom: 2rem;
  border-radius: 8px;
}

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

.btn {
  display: inline-block;
  background: #3498db;
  color: white;
  padding: 0.75rem 1.5rem;
  border-radius: 5px;
  margin-top: 1rem;
  transition: background 0.3s;
}

.btn:hover {
  background: #2980b9;
}

.page-header h1 {
  text-align: center;
  margin-bottom: 2rem;
  font-size: 2rem;
}

/* Products */
.products {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
}

.product-card {
  background: white;
  padding: 2rem;
  border-radius: 8px;
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

/* Downloads */
.downloads {
  background: white;
  padding: 2rem;
  margin-bottom: 2rem;
  border-radius: 8px;
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.download-links {
  margin-top: 1rem;
}

.download-links .btn {
  margin-right: 1rem;
  margin-bottom: 0.5rem;
}

/* Footer */
footer {
  text-align: center;
  padding: 1.5rem;
  background: #2c3e50;
  color: white;
  margin-top: 3rem;
}

/* Responsive */
@media (max-width: 768px) {
  nav {
    flex-direction: column;
    gap: 1rem;
  }

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

  .products,
  .download-links {
    grid-template-columns: 1fr;
  }
}