/* 全局设置 */
* { box-sizing: border-box; }
body {
  font-family: 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', Tahoma, Geneva, Verdana, sans-serif;
  margin: 0;
  padding: 0;
  background-color: #f4f4f9;
  color: #333;
  line-height: 1.6;
}
.container {
  max-width: 880px;
  margin: 0 auto;
  padding: 0 20px;
}

/* 头部：渐变背景 */
header {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
  padding: 60px 0 50px;
  text-align: center;
  border-radius: 0 0 24px 24px;
  box-shadow: 0 6px 20px rgba(118, 75, 162, 0.25);
}
header h1 { margin: 0; font-size: 2.1em; letter-spacing: 0.5px; }
header p { opacity: 0.92; margin-top: 12px; font-size: 1em; }
.tags { margin-top: 18px; }
.tag {
  display: inline-block;
  margin: 4px 5px 0;
  padding: 3px 12px;
  font-size: 0.8em;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.18);
  border: 1px solid rgba(255, 255, 255, 0.35);
}

/* 卡片布局 */
.category { margin-top: 42px; }
.category h2 {
  border-left: 5px solid #764ba2;
  padding-left: 12px;
  margin: 0 0 20px;
  font-size: 1.3em;
}
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 18px;
}
.card {
  background: #fff;
  padding: 20px;
  border-radius: 15px;
  text-decoration: none;
  color: inherit;
  transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
  border: 1px solid #eee;
  display: block;
}
.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 12px 24px rgba(118, 75, 162, 0.18);
  border-color: #764ba2;
}
.card h3 { margin: 0 0 8px; font-size: 1.05em; color: #2b2b33; }
.card p { margin: 0; color: #666; font-size: 0.9em; }

/* 底部 */
footer {
  text-align: center;
  padding: 48px 0 40px;
  color: #999;
  font-size: 0.85em;
}
footer p { margin: 4px 0; }
footer a { color: #764ba2; text-decoration: none; }
footer .muted { font-size: 0.85em; opacity: 0.8; }

@media (max-width: 480px) {
  header { padding: 44px 0 38px; }
  header h1 { font-size: 1.5em; }
  .category { margin-top: 32px; }
}