body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  background-color: lightgray;
}

header {
  background-color: lightblue;
  color: #fff;
  padding: 20px;
  text-align: center;
}

main {
  padding: 20px;
}

.posts {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}

.post {
  background-color: #fff;
  padding: 15px;
  border-radius: 5px;
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

footer {
  text-align: center;
  padding: 20px;
  background-color: lightblue;
  color: #fff;
}