body {
  margin: 0;
  font-family: Arial, sans-serif;
  transition: background-color 0.3s, color 0.3s;
}

.container {
  display: grid;
  grid-template-rows: auto 1fr auto;
  grid-template-columns: 200px 1fr;
  grid-template-areas:
      "header header"
      "sidebar main"
      "footer footer";
  height: 100vh;
}

header {
  grid-area: header;
  background-color: #4CAF50;
  color: white;
  padding: 10px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

header h1 {
  margin: 0;
  font-size: 1.2rem;
}

.theme-switch {
  font-size: 0.9rem;
}

aside {
  grid-area: sidebar;
  background-color: #f4f4f4;
  padding: 20px;
}

aside a {
  display: block;
  color: #333;
  text-decoration: none;
  margin: 10px 0;
}

aside a:hover {
  text-decoration: underline;
}

main {
  grid-area: main;
  padding: 20px;
}

footer {
  grid-area: footer;
  background-color: #4CAF50;
  color: white;
  text-align: center;
  padding: 10px;
}

body.dark-mode {
  background-color: #121212;
  color: #ddd;
}

body.dark-mode header {
  background-color: #222;
}

body.dark-mode aside {
  background-color: #333;
}

body.dark-mode aside a {
  color: #bbb;
}

body.dark-mode footer {
  background-color: #222;
}

body.dark-mode main {
  background-color: #121212;
}