/* Add a black background color to the top navigation */
.topnav {
    background-color: #333;
    overflow: hidden;
}

/* Style the links inside the navigation bar */
.topnav a {
    float: left;
    color: #f2f2f2;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
    font-size: 17px;
}

/* Change the color of links on hover */
.topnav a:hover {
    background-color: #ddd;
    color: black;
}

/* Add a color to the active/current link */
.topnav a.active {
    background-color: #4CAF50;
    color: white;
}


body
{
    text-align: center;
    margin: 0 auto;
}

#body {
    max-width: 2100px;
    min-width: 900px;
    height: 900px;
    margin: 0 auto;
}


/* Style the button that is used to open and close the collapsible content */
.collapsible {
    background-color: #eee;
    color: #444;
    cursor: pointer;
    padding: 18px;
    width: 100%;
    border: none;
    text-align: left;
    outline: none;
    font-size: 15px;
}

/* Add a background color to the button if it is clicked on (add the .active class with JS), and when you move the mouse over it (hover) */
.active, .collapsible:hover {
    background-color: #ccc;
}

/* Style the collapsible content. Note: hidden by default */
.content {
    padding: 0 18px;
    display: none;
    overflow: hidden;
    background-color: #f1f1f1;
}