styles.css

<link href='http://fonts.googleapis.com/css?family=Alegreya+Sans:100,300,400,500,700,800,900,100italic,300italic,400italic,500italic,700italic,800italic,900italic' rel='stylesheet' type='text/css'>
<link href='http://fonts.googleapis.com/css?family=Arvo:400,700,400italic' rel='stylesheet' type='text/css'>
<link href='http://fonts.googleapis.com/css?family=PT+Mono' rel='stylesheet' type='text/css'>
<link href='http://fonts.googleapis.com/css?family=Shadows+Into+Light' rel='stylesheet' type='text/css'>
<link href='http://fonts.googleapis.com/css?family=Nixie+One' rel='stylesheet' type='text/css'>
<link href='https://fonts.googleapis.com/css?family=Source+Code+Pro' rel='stylesheet' type='text/css'>
<link href="https://fonts.googleapis.com/css?family=Roboto+Slab:300,400,700" rel="stylesheet">
<style>

@font-face {
    font-family: "Computer Modern";
    src: url('http://mirrors.ctan.org/fonts/cm-unicode/fonts/otf/cmunss.otf');
}

#notebook_panel { /* main background */
    background: rgb(245,245,245);
}

div.cell { /* set cell width */
    width: 1000px;
}

div #notebook { /* centre the content */
    background: #fff; /* white background for content */
    width: 1200px;
    margin: auto;
    padding-left: 0em;
}

#notebook li { /* More space between bullet points */
    margin-top:0.8em;
}

/* draw border around running cells */
div.cell.border-box-sizing.code_cell.running { 
    border: 1px solid #111;
}

/* Put a solid color box around each cell and its output, visually linking them*/
div.cell.code_cell {
    background-color: rgb(256,256,256); 
    border-radius: 0px; 
    padding: 0.5em;
    margin-left:1em;
    margin-top: 1em;
}

div.text_cell_render{
    font-family: 'Alegreya Sans' sans-serif;
    line-height: 140%;
    font-size: 125%;
    font-weight: 400;
    width:900px;
    margin-left:auto;
    margin-right:auto;
}

.text_cell_render h1, .text_cell_render h2, .text_cell_render h3, .text_cell_render h4, .text_cell_render h5, .text_cell_render h6 {
    font-family: 'Roboto Slab', serif;
    font-weight: 400;
}

/* Formatting for header cells */
.text_cell_render h1 { 
    font-size: 28pt;
    line-height: 100%;
    color: rgb(0,51,102);
    margin-bottom: 0.2em;
    margin-top: 0.5em;
    display: block;
}

.text_cell_render h2 {
    font-size: 24pt;
    line-height: 100%;
    color: rgb(0,51,102);
    margin-bottom: 0.1em;
    margin-top: 0.3em;
    display: block;
}	

.text_cell_render h3 {
    margin-top:16px;
    font-size: 20pt;
    margin-bottom: 3px;
    font-style: regular;
    color: rgb(102,102,0);
}

.text_cell_render h4 {    /*Use this for captions*/
    /*text-align: center;*/
    margin-top: 1em;
    margin-bottom: 1em;
    font-style: regular;
}

.text_cell_render h5 {  /*Use this for small titles*/
    font-size: 16pt;
    color: rgb(163,0,0);
    font-style: italic;
    margin-bottom: .1em;
    margin-top: 0.8em;
    display: block;
}

.text_cell_render h6 { /*use this for copyright note*/
    font-family: 'PT Mono', sans-serif;
    font-weight: 300;
    font-size: 12pt;
    line-height: 100%;
    color: grey;
    margin-bottom: 1px;
    margin-top: 1px;
}

.text_cell_render p {
    text-align: justify
}

.CodeMirror{
    font-family: "Source Code Pro";
    font-size: 100%;
}

.alert-box {
    padding:10px 10px 10px 36px;
    margin:5px;
}

.success {
    color:#666600;
    background:rgb(240,242,229);
}

/* Custom Images with Caption*/

.imgWithCaption
{
    text-align: center;
        padding-top: 18pt;
}

.imgWithCaption > img:before
{
  content: '';
  height: 100%;
  display: inline-block;
  vertical-align: middle;

}

.imgWithCaption > img
{
    padding: 5px;
    display: inline-block;
    vertical-align: middle;
    border: 2pt solid #EEE;
}

.imgWithCaption > .caption
{
  margin: auto;
  padding-top : 12pt;
  padding-bottom : 12pt;
  padding-left : 18pt;
  padding-right : 18pt;
  font-size: 12pt;
}


</style>

<script>
  

  MathJax.Ajax.config.path["Contrib"] = "//cdn.mathjax.org/mathjax/contrib";

  MathJax.Hub.Config({
          extensions: [ "[Contrib]/counters/counters.js" ],
          "HTML-CSS": {
              styles: {'.MathJax_Display': {"margin": 4}},
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            preferredFont: "TeX",
            webFont: "TeX"
          },
          TeX: {
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             equationNumbers: { autoNumber: "all" },
             Augment: {
               Definitions: {macros: {
                 unitfrac: "myUnitFrac"
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                   var n = this.GetBrackets(name),
                       num = this.GetArgument(name),
                       den = this.GetArgument(name);
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          tex2jax: {
              inlineMath: [ ['$','$'], ["\\(","\\)"] ],
              displayMath: [ ['$$','$$'], ["\\[","\\]"] ]
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          displayAlign: 'center' 
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  $("<style type='text/css'> .cell.code_cell.collapse { max-height:30px; overflow:hidden;} </style>").appendTo("head");
  $('.prompt.input_prompt').on('click', function(event) {
      console.log("CLICKED", arguments)   
      var c = $(event.target.closest('.cell.code_cell'))
      if(c.hasClass('collapse')) {
          c.removeClass('collapse');
      } else {
          c.addClass('collapse');
      }
  });
  
</script>