@media screen and (max-width: 520px) {

    .content > * {
        width: 90%;
        padding-top: 1em;
        padding-bottom: 2em;
    }

    .activity-area {
        display: flex;
        flex-flow: column;
        align-items: center;
        justify-content: space-evenly;
    }

    .activity {
        width: 100%;
        margin-bottom: 1em;
    }

    .menu {
        display: none;
    }

    .sp-menu-btn {
        display: block;
    }

    .menu-item {
        margin: 0;
        padding-left: 1em;
        border-bottom: 1px solid;
    }

}