.sidebar {
    padding: 0;
    width: 25%;
    background-color: #f1f1f1;
    height: 100%;
    overflow: auto;
    transition: width .3s linear;
    height: 800px;
    float:right;
}
div.content {
    padding: 1px 16px;
    height: auto;
    float: left;
    width: 75%;
}
@media screen and (max-width: 700px) {
    .sidebar {
        width: 100%;
        height: auto;
        float: left;
    }
    div.content {
        margin-left: 0;
        width: 100%;
        float: none;
    }
}
@media screen and (max-width: 400px) {
    .sidebar a {
        text-align: center;
        float: none;
    }
}