CSS-Template_using_Flexbox

index.html

<!DOCTYPE html>
<html lang="en">
<head>
<title>CSS Template</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">

<link rel="stylesheet" href="style.css">

</head>
<body>

<h2>CSS Template using Flexbox</h2>
<p>In this example, we have created a header, three equal columns and a footer. On smaller screens, the columns will stack on top of each other.</p>
<p>Resize the browser window to see the responsive effect.</p>
<p><strong>Note:</strong> Flexbox is not supported in Internet Explorer 10 eand earlier versions.</p>

<div class="header">
  <h2>Header</h2>
</div>

<div class="row">
  <div class="column" style="background-color:#aaa;">Column</div>
  <div class="column" style="background-color:#bbb;">Column</div>
  <div class="column" style="background-color:#ccc;">Column</div>
  <div class="column" style="background-color:#bbb;">Column</div>
</div>

<div class="footer">
  <p>Footer</p>
</div>

</body>
</html>

style.css

* {
    box-sizing: border-box;
}
  
body {
    font-family: Arial, Helvetica, sans-serif;
}
  
/* Style the header */
.header {
    background-color: #f1f1f1;
    padding: 30px;
    text-align: center;
    font-size: 35px;
}
  
/* Container for flexboxes */
.row {
    display: -webkit-flex;
    display: flex;
}

/* Create three equal columns that sits next to each other */
.column {
    -webkit-flex: 1;
    -ms-flex: 1;
    flex: 1;
    padding: 10px;
    height: 300px; /* Should be removed. Only for demonstration */
}

/* Style the footer */
.footer {
    background-color: #f1f1f1;
    padding: 10px;
    text-align: center;
}

/* Responsive layout - makes the three columns stack on top of each other instead of next to each other */
@media (max-width: 600px) {
.row {
    -webkit-flex-direction: column;
    flex-direction: column;
    }
}

Document

menu

Document in project

You can download PDF file.

Refference