Responsive layout with sidebar css Code Snippet in 2025

Creates a responsive layout with a content area and a sidebar.

• Use display: grid on the parent container, to create a grid layout.
• Use minmax() for the second column (sidebar) to allow it to take up between 150px and 20%.
• Use 1fr for the first column (main content) to take up the rest of the remaining space.

<div class="container">
  <main>
    This element is 1fr large.
  </main>
  <aside>
    Min: 150px / Max: 20%
  </aside>
</div>

.container {
  display: grid;
  grid-template-columns: 1fr minmax(150px, 20%);
  height: 100px;
}

main, aside {
  padding: 12px;
  text-align: center;
}

main {
  background: #d4f2c4;
}

aside {
  background: #81cfd9;
}