Build a Responsive Full-Page Layout with CSS Grid

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

.grid-container {
  display: grid;
  grid-template-rows: auto 1fr auto; /* Header, Main content (grows), Footer */
  grid-template-columns: 1fr; /* Single column by default */
  grid-template-areas:
    "header"
    "main"
    "footer";
  min-height: 100vh; /* Ensures layout takes full viewport height */
}

header {
  grid-area: header;
  background-color: #333;
  color: white;
  padding: 1em;
  text-align: center;
}

main {
  grid-area: main;
  padding: 1em;
  background-color: #f4f4f4;
}

footer {
  grid-area: footer;
  background-color: #333;
  color: white;
  padding: 1em;
  text-align: center;
}

/* Responsive layout for larger screens */
@media (min-width: 768px) {
  .grid-container {
    grid-template-columns: 200px 1fr; /* Sidebar, Main content */
    grid-template-areas:
      "header header"
      "nav    main"
      "footer footer";
  }
  nav {
    grid-area: nav;
    background-color: #555;
    color: white;
    padding: 1em;
  }
  /* Include a nav element in HTML for this media query */
}
/* HTML Structure */
/*
<div class="grid-container">
  <header>Header</header>
  <nav>Navigation</nav> (Optional, uncomment for larger screens)
  <main>Main Content</main>
  <footer>Footer</footer>
</div>
*/