Holy Grail layout is a layout with a fixed height header and footer, and a center with 3 columns. The 3 columns include a fixed width sidenav, a fluid center, and a column for other content like ads (the fluid center appears first in the markup). CSS Flexbox can be used to achieve this with a very simple markup:
HTML Markup:
<div class="container">
<header class="header">Header</header>
<div class="content-body">
<main class="content">Content</main>
<nav class="sidenav">Nav</nav>
<aside class="ads">Ads</aside>
</div>
<footer class="footer">Footer</footer>
</div>
CSS:
body {
margin: 0;
padding: 0;
}
.container {
display: flex;
flex-direction: column;
height: 100vh;
}
.header {
flex: 0 0 50px;
}
.content-body {
flex: 1 1 auto;
display: flex;
flex-direction: row;
}
.content-body .content {
flex: 1 1 auto;
overflow: auto;
}
.content-body .sidenav {
order: -1;
flex: 0 0 100px;
overflow: auto;
}
.content-body .ads {
flex: 0 0 100px;
overflow: auto;
}
.footer {
flex: 0 0 50px;
}