diff --git a/assets/css/bootstrap.css b/assets/css/bootstrap.css
index 0fe7cd5b..6704f50c 100644
--- a/assets/css/bootstrap.css
+++ b/assets/css/bootstrap.css
@@ -107,6 +107,7 @@ pre,
 samp {
   font-family: monospace, monospace;
   font-size: 1em;
+  hyphens: none;
 }
 button,
 input,
diff --git a/assets/css/lesson.scss b/assets/css/lesson.scss
index fe008e50..6e9e81ea 100644
--- a/assets/css/lesson.scss
+++ b/assets/css/lesson.scss
@@ -29,32 +29,38 @@ $color-testimonial: #fc8dc1 !default;
 //----------------------------------------
 
 @mixin cdSetup($color) {
-  color: $color;
-  border-left: solid 5px $color;
-  margin-bottom: 0px;
-  border-radius: 4px 0 0 4px;
+    color: $color;
+    border-left: solid 5px $color;
+    margin: 15px 0;
+    border-radius: 4px 0 0 4px;
 }
 
 .error  { @include cdSetup($color-error); }
 .output { @include cdSetup($color-output); }
 .source { @include cdSetup($color-source); }
 
-.bash   { @include cdSetup($color-source); }
-.make   { @include cdSetup($color-source); }
-.matlab { @include cdSetup($color-source); }
-.python { @include cdSetup($color-source); }
-.r      { @include cdSetup($color-source); }
-.sql    { @include cdSetup($color-source); }
+.bash, .language-bash     { @include cdSetup($color-source); }
+.make, .language-make     { @include cdSetup($color-source); }
+.matlab, .language-matlab { @include cdSetup($color-source); }
+.python, .language-python { @include cdSetup($color-source); }
+.r, .language-r           { @include cdSetup($color-source); }
+.sql, .language-sql       { @include cdSetup($color-source); }
 
 .error pre,
 .output pre,
 .source pre,
 .bash pre,
+.language-bash pre,
 .make pre,
+.language-make pre,
 .matlab pre,
+.language-matlab pre,
 .python pre,
+.language-python pre,
 .r pre,
-.sql pre {
+.language-r pre,
+.sql pre ,
+.language-sql pre {
   border-radius: 0 4px 4px 0;
 }
 
@@ -75,8 +81,11 @@ $codeblock-padding: 5px !default;
   padding-right: 0;
   border: 1px solid;
   border-color: $color;
+  border-radius: 4px;
   padding-bottom: $codeblock-padding;
 
+  margin: 15px 0;
+
   h2 {
     padding-top: $codeblock-padding;
     padding-bottom: $codeblock-padding;
@@ -108,24 +117,54 @@ $codeblock-padding: 5px !default;
 .solution{ @include bkSetup($color-solution, "\e105"); }
 .testimonial{ @include bkSetup($color-testimonial, "\e143"); }
 
+.callout h3,
+.challenge h3,
+.checklist h3,
+.discussion h3,
+.keypoints h3,
+.objectives h3,
+.prereq h3,
+.solution h3,
+.testimonial h3 {
+font-size: 18px;
+}
+
+blockquote p {
+    margin: 5px;
+}
+
 //----------------------------------------
 // Override Bootstrap settings.
 //----------------------------------------
 
 code {
+  white-space: nowrap;
   padding: 2px 5px;
   color: #3d90d9;
   background-color: #e7e7e7;
 }
 
-img {
-  max-width: 100%;
+article img {
+    display: block;
+    margin: 20px auto;
+    max-width: 100%;
+}
+
+article h2 {
+  margin: 48px 0 16px;
+  border-bottom: solid 1px #eaecef;
+  padding-bottom: 0.3em;
+  line-height: 1.25;
 }
 
+article h3 { margin: 40px 0 16px; }
+
 //----------------------------------------
 // Miscellaneous.
 //----------------------------------------
 
+.figures h2 { margin-top: 100px; }
+
 .maintitle {
   text-align: center;
 }
@@ -134,6 +173,16 @@ img {
   text-align: center;
 }
 
+footer .copyright,
+footer .help-links
+{
+    font-size: inherit;
+    margin-top: 10px;
+    margin-bottom: 10px;
+    font-weight: 500;
+    line-height: 1.1;
+}
+
 img.navbar-logo {
   height: 40px; // synchronize with height of navbar
   padding-top: 5px;
@@ -153,3 +202,56 @@ span.fold-unfold {
   margin-left: 1em;
   opacity: 0.5;
 }
+
+
+//----------------------------------------
+// Life cycle box
+//----------------------------------------
+
+div.life-cycle {
+    position: -webkit-sticky; /* Safari */
+    position: sticky;
+    top: 0;
+    z-index: 100;
+    font-size: 1.2em;
+    text-align: center;
+    margin-bottom: -1px;
+    border-radius: 0;
+}
+
+.pre-alpha {
+    color: #a94442;
+    background: #f2dede;
+}
+
+.alpha {
+    color: #8a6d3b;
+    background: #fcf8e3;
+}
+
+.beta {
+    color: #31708f;
+    background: #d9edf7;
+}
+
+
+//----------------------------------------
+// keyboard key style, from StackExchange.
+//----------------------------------------
+
+kbd {
+    display: inline-block;
+    margin: 0 .1em;
+    padding: .1em .6em;
+    font-family: Arial,"Helvetica Neue",Helvetica,sans-serif;
+    font-size: 11px;
+    line-height: 1.4;
+    color: #242729;
+    text-shadow: 0 1px 0 #FFF;
+    background-color: #e1e3e5;
+    border: 1px solid #adb3b9;
+    border-radius: 3px;
+    box-shadow: 0 1px 0 rgba(12,13,14,0.2), 0 0 0 2px #FFF inset;
+    white-space: nowrap;
+    font-style: normal;
+}
diff --git a/assets/css/syntax.css b/assets/css/syntax.css
new file mode 100644
index 00000000..572069c1
--- /dev/null
+++ b/assets/css/syntax.css
@@ -0,0 +1,69 @@
+.highlight .hll { background-color: #ffffcc }
+.highlight  { background: #f8f8f8; }
+.highlight .c { color: #408080; font-style: italic } /* Comment */
+.highlight .err { border: 1px solid #FF0000 } /* Error */
+.highlight .k { color: #008000; font-weight: bold } /* Keyword */
+.highlight .o { color: #666666 } /* Operator */
+.highlight .ch { color: #408080; font-style: italic } /* Comment.Hashbang */
+.highlight .cm { color: #408080; font-style: italic } /* Comment.Multiline */
+.highlight .cp { color: #BC7A00 } /* Comment.Preproc */
+.highlight .cpf { color: #408080; font-style: italic } /* Comment.PreprocFile */
+.highlight .c1 { color: #408080; font-style: italic } /* Comment.Single */
+.highlight .cs { color: #408080; font-style: italic } /* Comment.Special */
+.highlight .gd { color: #A00000 } /* Generic.Deleted */
+.highlight .ge { font-style: italic } /* Generic.Emph */
+.highlight .gr { color: #FF0000 } /* Generic.Error */
+.highlight .gh { color: #000080; font-weight: bold } /* Generic.Heading */
+.highlight .gi { color: #00A000 } /* Generic.Inserted */
+.highlight .go { color: #888888 } /* Generic.Output */
+.highlight .gp { color: #000080; font-weight: bold } /* Generic.Prompt */
+.highlight .gs { font-weight: bold } /* Generic.Strong */
+.highlight .gu { color: #800080; font-weight: bold } /* Generic.Subheading */
+.highlight .gt { color: #0044DD } /* Generic.Traceback */
+.highlight .kc { color: #008000; font-weight: bold } /* Keyword.Constant */
+.highlight .kd { color: #008000; font-weight: bold } /* Keyword.Declaration */
+.highlight .kn { color: #008000; font-weight: bold } /* Keyword.Namespace */
+.highlight .kp { color: #008000 } /* Keyword.Pseudo */
+.highlight .kr { color: #008000; font-weight: bold } /* Keyword.Reserved */
+.highlight .kt { color: #B00040 } /* Keyword.Type */
+.highlight .m { color: #666666 } /* Literal.Number */
+.highlight .s { color: #BA2121 } /* Literal.String */
+.highlight .na { color: #7D9029 } /* Name.Attribute */
+.highlight .nb { color: #008000 } /* Name.Builtin */
+.highlight .nc { color: #0000FF; font-weight: bold } /* Name.Class */
+.highlight .no { color: #880000 } /* Name.Constant */
+.highlight .nd { color: #AA22FF } /* Name.Decorator */
+.highlight .ni { color: #999999; font-weight: bold } /* Name.Entity */
+.highlight .ne { color: #D2413A; font-weight: bold } /* Name.Exception */
+.highlight .nf { color: #0000FF } /* Name.Function */
+.highlight .nl { color: #A0A000 } /* Name.Label */
+.highlight .nn { color: #0000FF; font-weight: bold } /* Name.Namespace */
+.highlight .nt { color: #008000; font-weight: bold } /* Name.Tag */
+.highlight .nv { color: #19177C } /* Name.Variable */
+.highlight .ow { color: #AA22FF; font-weight: bold } /* Operator.Word */
+.highlight .w { color: #bbbbbb } /* Text.Whitespace */
+.highlight .mb { color: #666666 } /* Literal.Number.Bin */
+.highlight .mf { color: #666666 } /* Literal.Number.Float */
+.highlight .mh { color: #666666 } /* Literal.Number.Hex */
+.highlight .mi { color: #666666 } /* Literal.Number.Integer */
+.highlight .mo { color: #666666 } /* Literal.Number.Oct */
+.highlight .sa { color: #BA2121 } /* Literal.String.Affix */
+.highlight .sb { color: #BA2121 } /* Literal.String.Backtick */
+.highlight .sc { color: #BA2121 } /* Literal.String.Char */
+.highlight .dl { color: #BA2121 } /* Literal.String.Delimiter */
+.highlight .sd { color: #BA2121; font-style: italic } /* Literal.String.Doc */
+.highlight .s2 { color: #BA2121 } /* Literal.String.Double */
+.highlight .se { color: #BB6622; font-weight: bold } /* Literal.String.Escape */
+.highlight .sh { color: #BA2121 } /* Literal.String.Heredoc */
+.highlight .si { color: #BB6688; font-weight: bold } /* Literal.String.Interpol */
+.highlight .sx { color: #008000 } /* Literal.String.Other */
+.highlight .sr { color: #BB6688 } /* Literal.String.Regex */
+.highlight .s1 { color: #BA2121 } /* Literal.String.Single */
+.highlight .ss { color: #19177C } /* Literal.String.Symbol */
+.highlight .bp { color: #008000 } /* Name.Builtin.Pseudo */
+.highlight .fm { color: #0000FF } /* Name.Function.Magic */
+.highlight .vc { color: #19177C } /* Name.Variable.Class */
+.highlight .vg { color: #19177C } /* Name.Variable.Global */
+.highlight .vi { color: #19177C } /* Name.Variable.Instance */
+.highlight .vm { color: #19177C } /* Name.Variable.Magic */
+.highlight .il { color: #666666 } /* Literal.Number.Integer.Long */
diff --git a/assets/js/lesson.js b/assets/js/lesson.js
index d5b465fe..333dee8c 100644
--- a/assets/js/lesson.js
+++ b/assets/js/lesson.js
@@ -3,7 +3,7 @@ $("table").addClass("table table-striped");
 
 
 // Handle foldable challenges and solutions (on click and at start).
-$(".discussion,.solution").click(function(event) {
+$(".solution").click(function(event) {
     var trigger = $(event.target).has(".fold-unfold").size() > 0
                || $(event.target).filter(".fold-unfold").size() > 0;
     if (trigger) {
@@ -12,7 +12,7 @@ $(".discussion,.solution").click(function(event) {
         event.stopPropagation();
     }
 });
-$(".discussion,.solution").each(function() {
+$(".solution").each(function() {
     $(">*:not(h2)", this).toggle();
     var h2 = $("h2:first", this);
     h2.append("<span class='fold-unfold glyphicon glyphicon-collapse-down'></span>");
@@ -26,3 +26,31 @@ function google_search() {
   var domain = $("meta[name=search-domain]").attr("value");
   window.open("https://www.google.com/search?q=" + query + "+site:" + domain);
 }
+
+// function to shrink the life cycle bar when scrolling
+$(function(){
+    $('#life-cycle').data('size','big');
+});
+
+$(window).scroll(function(){
+    if($(document).scrollTop() > 0)
+    {
+        if($('#life-cycle').data('size') == 'big')
+        {
+            $('#life-cycle').data('size','small');
+            $('#life-cycle').stop().animate({
+                padding: '5px'
+            },100);
+        }
+    }
+    else
+    {
+        if($('#life-cycle').data('size') == 'small')
+        {
+            $('#life-cycle').data('size','big');
+            $('#life-cycle').stop().animate({
+                padding: '15px'
+            },100);
+        }
+    }
+});