.toplevel_page_activity-ninja {
    .nav-tab-wrapper {
        margin-bottom: 20px;
    }

    .nav-tab {
        padding: 10px 15px;
        text-decoration: none;
        border: 1px solid #ccc;
        background: #f9f9f9;
        margin-right: 5px;
    }

    .nav-tab-active {
        background: #fff;
        font-weight: bold;
        border-bottom: 1px solid #fff;
    }

    .tab-content {
        padding: 20px;
        border: 1px solid #ccc;
        background: #fff;
    }
}