custom.css

<style>
    @font-face {
        font-family: "Computer Modern";
        src: url('http://mirrors.ctan.org/fonts/cm-unicode/fonts/otf/cmunss.otf');
    }
    div.cell{
        width: 90%;
/*        margin-left:auto;*/
/*        margin-right:auto;*/
    }
    ul {
        line-height: 145%;
        font-size: 90%;
    }
    li {
        margin-bottom: 1em;
    }
    h1 {
        font-family: Helvetica, serif;
        color: rgb(0, 80, 120);
    }
    h2 {
        color: rgb(0,100,110);
    }
    h3 {
        color: rgb(94,127,192);
    }
    div.text_cell_render{
        font-family: Computer Modern, "Helvetica Neue", Arial, Helvetica, Geneva, sans-serif;
        line-height: 145%;
        font-size: 130%;
        width: 90%;
        margin-left:auto;
        margin-right:auto;
    }
    .CodeMirror{
            font-family: "Source Code Pro", source-code-pro,Consolas, monospace;
    }
/*    .prompt{
        display: None;
    }*/
    .text_cell_render h5 {
        font-weight: 300;
        font-size: 16pt;
        color: #4057A1;
        font-style: italic;
        margin-bottom: 0.5em;
        margin-top: 0.5em;
        display: block;
    }

    .warning{
        color: rgb( 240, 20, 20 )
        }
</style>
<script>
    MathJax.Hub.Config({
                        TeX: {
                           extensions: ["AMSmath.js"]
                           },
                tex2jax: {
                    inlineMath: [ ['$','$'], ["\\(","\\)"] ],
                    displayMath: [ ['$$','$$'], ["\\[","\\]"] ]
                },
                displayAlign: 'center', // Change this to 'center' to center equations.
                "HTML-CSS": {
                    styles: {'.MathJax_Display': {"margin": 4}}
                }
        });
</script>