SOURCE

<div class="container">
    <div class="middle">
        <div class="inner"></div>
    </div>
    <div class="left"></div>
    <div class="right"></div>
</div>

 * {
      margin: 0;
      padding: 0;
    }

.container {
    overflow: hidden;
}

.middle {
    float: left;
    width: 100%;
    background-color: rebeccapurple;
}

.inner {
    margin: 0 200px 0 100px;
    min-height: 200px;
    background-color: salmon;
}

.left {
    float: left;
    width: 100px;
    min-height: 100px;
    margin-left: -100%;
    background-color: rosybrown;
    padding-bottom: 999999px;
    margin-bottom: -999999px;
}

.right {
    float: left;
    width: 200px;
    min-height: 100px;
    margin-left: -200px;
    background-color: aqua;
}