body {
    margin: 0;
    font-family: Verdana, Geneva, Tahoma, sans-serif;
}

.name {
    font-family: verdana;
    font-size: 28px;
    text-align: center;
}

.personal_description {
    font-family: verdana;
    font-size: 12px;
    text-align: center;
}

.navigation_bar_lv1 {
    overflow: hidden;
    background-color: lightblue;
}

.navigation_bar_lv1 a {
    float: left;
    font-size: 16px;
    color: black;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
    background-color: inherit;
}

.navigation_bar_lv2 {
    float: left;
    overflow: hidden;
}

.navigation_bar_lv2 .navigation_bar_lv2_button {
    font-size: 16px;  
    border: none;
    outline: none;
    color: black;
    padding: 14px 16px;
    background-color: inherit;
    font-family: inherit;
    margin: 0;
}

.navigation_bar_lv1 a:hover, .navigation_bar_lv2:hover .navigation_bar_lv2_button {
    background-color: lightseagreen;
}

.navigation_bar_lv2_links {
    display: none;
    position: absolute;
    left: 0;
    background-color: lightseagreen;
    width: 100%;
    z-index: 1;
}

.navigation_bar_lv2_links button {
    float: left;
    color: white;
    text-decoration: none;
}

.navigation_bar_lv2_links a:hover {
    background-color: whitesmoke;
    color: black;
}

.navigation_bar_lv2:hover .navigation_bar_lv2_links {
    display: block;
}

.tick {
    visibility: hidden;
}

.open_button {
    font-size: 24;
}

.side_navigation {
    height: 100%;
    width: 0;
    background-color: black;
    position: fixed;
    z-index: 1;
    top: 0;
    left: 0;
    overflow-x: hidden;
    padding-top: 60px;
    transition: 0.5s;
}

.side_navigation a {
    text-decoration: none;
    font-size: 20px;
    color: lightslategray;
    display: block;
    padding: 8px 8px 8px 32px;
    transition: 0.3s;
}

.side_navigation a:hover {
    color: lightgoldenrodyellow;
}

.side_navigation .close_button {
    position: absolute;
    top: 0;
    right: 25px;
    font-size: 30px;
    margin-left: 50px;
}

#pushed_content {
    transition: margin-left .5s;
}

.course_content {
    background-color: lightcyan;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    /* display: none; */
}

.course_content h1 {
    color: darkblue;
}

.course_content h3 {
    color: brown;
}