Full-Page Layout with Header, Main, and Sticky Footer using CSS Grid

html, body {
  height: 100%;
  margin: 0;
  font-family: Arial, sans-serif;
}

body {
  display: grid;
  grid-template-rows: auto 1fr auto; /* Header (auto), Main (1fr), Footer (auto) */
  min-height: 100vh; /* Ensure body takes full viewport height */
}

header {
  background-color: #f0f0f0;
  padding: 20px;
  text-align: center;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

main {
  background-color: #ffffff;
  padding: 20px;
}

footer {
  background-color: #333;
  color: white;
  padding: 15px;
  text-align: center;
}

How it works: This snippet creates a common full-page layout using CSS Grid for a 'sticky footer' effect. The `body` element is set to `display: grid;` and `min-height: 100vh;` to occupy the full viewport height. `grid-template-rows: auto 1fr auto;` defines three rows: `auto` for the header (takes content height), `1fr` for the main content (expands to fill all remaining space, pushing the footer down), and `auto` for the footer (takes content height). This ensures the footer always stays at the bottom, regardless of main content length.