*{
    box-sizing: border-box;
}

body{
    margin: 0;
    background-color: lightgray;
    line-height: 1.4;
}

.container{
    max-width: 960px;
    margin: 0 auto;
    outline: 3px dotted purple;
}

.row{
    display: flex;
}

.flex-item{
    flex-basis: 300px;
    height: 150px;
}

.one{
    background-color: tomato;
    -flex-grow: 3;
    flex-shrink: 5;
}

.two{
    background-color: cadetblue;
    -flex-grow: 2;
}

.three{
    background-color: saddlebrown;
}