Untitled

<html>
<head>
    <style>
        body {
            margin: 0
        }

        div#outer-container {
            height: 100%;
        }

        div#inner-container {
            display: flex;
            height: 100%;
            flex-direction: row;
        }

        div #left {flex: 1; background-color: yellow;}
        div #center {flex: 5; background-color: #fdd;}
        div #right {flex: 1; background-color: pink;}
    </style>
</head>
<body>

    <div id="outer-container">
        <div>HEADER</div>
        <div id="inner-container">
            <div id="left"></div>
            <div id="center"></div>
            <div id="right"></div>
        </div>
        <div>FOOTER</div>
    </div>
</body>
</html>