body, html {
    width: 100%;
    height: 100%;
    margin: 0;
}

.container {
    width: 100%;
    height: 100%;
}

.leftpane {
    width: 70%;
    height: 100%;
    float: left;
    border-collapse: collapse;
}

.rightpane {
    width: 28%;
    height: 100%;
    position: relative;
    float: right;
    border-collapse: collapse;
}

.flex_container {
    display: flex;
    flex-wrap: wrap;
    align-items: stretch;
}

.box {
    margin: 4px;
    border: 1px solid black;
    width: 100px;
    height: 100px;
    text-align: left;
    word-wrap: break-word;
    text-align: center;
}