.demo-container {
    display: flex;
    justify-content: center;
    height: 450px;
}

.buttons-demo {
    width: 600px;
    align-self: center;
}

.header {
    display: flex;
    flex-wrap: nowrap;
}

.header > div {
    flex-grow: 0;
    flex-basis: 120px;
    height: 30px;
}

.types {
    width: 120px;
    display: flex;
    flex-direction: column;
    float: left;
}

.types > div {
    flex-grow: 1;
    padding: 10px;
    height: 30px;
    line-height: 20px;
    font-weight: bold;
    opacity: 0.7;
}

.buttons {
    display: flex;
    flex-wrap: wrap;
    margin-left: 120px;
}

.buttons > div {
    flex-basis: 120px;
    height: 50px;
}