@media screen and (min-width: 900px) {
            #Cols {
                column-gap: 20px;
                column-count: 2;
            }
        }
    </style>
</head>

<body class='body'>
    <nav>
        Examples:
        <a href='/sections' class='active'>Sections</a>
        <a href='/document'>Document</a>
        <a href='/multilang'>Multilingual Document</a>
        <a href='/uilangs'>UI Language</a>
        <a href='/math'>Math</a>
        <a href='/hideexitbutton'>Hide Exit Button</a>
        <