.hourbox {
    border: solid 1px #888;
    background-color: #fff;
    color: #888;
    border-right: 0px;
    width: 20px;
    display: inline-block;
    margin: 0px;
    font-size: 0.8em;
    text-align: center;
}

.break {
    flex-basis: 100%;
    height: 0;
    display:none;
  }

.hourbox.end {
    border-right: solid 1px #888;
}

@media only screen and (max-width: 660px) {
    .break {
        display: block;
    }
}