/* 全局样式 */
body {
  margin: 0;
  padding: 0;
  font-family: 'Roboto', sans-serif;
  background-color: #F5F5F5;
  color: #333;
  line-height: 1.6;
  overflow-x: hidden;
}
header {
  background-color: #0074D9;
  color: #fff;
  padding: 20px 10px;
  text-align: center;
  position: sticky;
  top: 0;
  z-index: 1000;
}
header h1 {
  font-size: 2rem;
  margin: 0;
}
main {
  padding: 20px;
  display: grid;
  gap: 20px;
}
@media (min-width: 768px) {
  main {
    grid-template-columns: repeat(2, 1fr);
  }
}
@media (min-width: 1024px) {
  main {
    grid-template-columns: repeat(3, 1fr);
  }
}
footer {
  background-color: #0074D9;
  color: #fff;
  text-align: center;
  padding: 10px 0;
  position: relative;
}
.card {
  background-color: #fff;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  border-radius: 8px;
  padding: 20px;
  text-align: center;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}
.card img {
  width: 100%;
  height: auto;
  border-radius: 8px;
}
.btn {
  background-color: #FFA500;
  color: #fff;
  padding: 10px 20px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  transition: background-color 0.3s ease;
}
.btn:hover {
  background-color: #e69500;
}
.matrix {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
  margin-top: 20px;
}
.matrix-item {
  background-color: #fff;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  border-radius: 8px;
  padding: 16px;
  text-align: center;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.matrix-item:hover {
  transform: scale(1.05);
  box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}
.article {
  background-color: #fff;
  padding: 20px;
  border-radius: 8px;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}
.article h2 {
  color: #0074D9;
}
.article pre {
  background-color: #f4f4f4;
  padding: 10px;
  border-radius: 4px;
  overflow-x: auto;
}
@media (max-width: 768px) {
  main {
    grid-template-columns: 1fr;
  }
  .matrix {
    grid-template-columns: 1fr;
  }
}