styles.css

.app {
    height: 100%;
    display: flex;
    overflow: hidden;
    background: white;
    font-family: "Trebuchet MS", Helvetica, sans-serif;
    flex-direction: column;
    color: #333331;
    line-height: 1.6em;
}


.app .content {
    height: 100%;
    padding: 1em;
    flex-grow: 1;
    overflow-y: scroll;
}

.app .content img {
    width: 100%;
    height: auto;
}

.app ul {
    display: flex;
    flex-direction: row;
    list-style: none;
    margin: 0;
    padding: 0;
}

.app ul li {
    flex: 1;
    height: 4em;
    cursor: pointer;
    display: block;
    text-align: center;
    background: linear-gradient(to bottom, #6b6b6b 0%,#464545 100%);
    line-height: 4em;
    text-transform: uppercase;
    font-weight: bold;
    color: #dadada;
}

.app ul li.current, .app ul li:hover {
    background: linear-gradient(to bottom, #464545 0%,#6b6b6b 100%);
}