Complete Code For Using Flex Basis Property With CSS Animation.
<!DOCTYPE html> <html> <head> <title>How Do I Use Flex Basis Property With CSS Animation</title> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css"/> </head> <style> * { box-sizing: border-box; } body { background-color: #666699; } #main { width: 100%; height: 100px; border: 5px solid #c3c3c3; display: flex; } #main div { flex-grow: 0; flex-shrink: 0; flex-basis: 50px; } #myBlueDiv { animation: mymove 5s infinite; } @keyframes mymove { 50% {flex-basis: 80%;} } </style> <body> <br/><br/> <div class="container"> <br> <div class="text-center"> <h1 id="color" style="color: white;">Flex Basis Property With CSS Animation</h1> </div> <div class="well"> <div id="main"> <div style="background-color:#cc0000;">RED</div> <div style="background-color:#3399ff;" id="myBlueDiv">BLUE</div> </div> </div> </div> </body> </html>