body {
  margin: 0;
  font-family: Arial, sans-serif;
}

header {
  background-color: #333;
  color: white;
  padding: 10px 0;
}

nav ul {
  display: flex;
  justify-content: center;
  list-style: none;
  margin: 0;
  padding: 0;
}

nav ul li {
  margin: 0 15px;
}

nav ul li a {
  color: white;
  text-decoration: none;
}

main {
  display: flex;
  flex-direction: row;
  height: calc(100vh - 80px); 
}

.left-sidebar {
  background-color: #f4a261;
  flex: 1;
}

.content {
  background-color: #e76f51;
  flex: 2;
}

.right-sidebar {
  background-color: #2a9d8f;
  flex: 1;
}

footer {
  background-color: #264653;
  color: white;
  text-align: center;
  padding: 10px 0;
  position: absolute;
  bottom: 0;
  width: 100%;
}

@media (max-width: 768px) {
  nav ul {
    flex-direction: column;
    text-align: center;
  }

  main {
    flex-direction: column;
  }

  .left-sidebar, .right-sidebar {
    flex: 0;
    height: 100px; 
  }
}