Embed DartPad in the top part of homepage

src/site/css/dart-style.css

 body {
   font-family: 'Roboto', sans-serif;
   font-size: 15px;
   -webkit-font-smoothing: antialiased;
 }
 
 /* ***** General ***** */
 p,
 dt,
 dd {
@@ skipping 201 matching lines @@
     display: none;
   }
 }
 
 i.sprite-icon-close-x {
   width: 8px;
   height: 8px;
   background-position: -150px -200px;
 }
 
+.btn-lg.try-btn {
+  padding: 10px 46px 10px 46px;
+  position: relative;
+}
+
 .btn-lg.download-btn {
   padding: 10px 46px 10px 66px;
   position: relative;
 }
 
 i.sprite-icon-download-btn {
   position: absolute;
   left: 40px;
   width: 14px;
   height: 18px;
@@ skipping 518 matching lines @@
 
 .hero p {
   color: #fff;
 }
 
 .hero a {
   color: #fff;
   text-decoration: underline;
 }
 
-.hero .download-btn {
+.hero .download-btn, .hero .try-btn {
   background: none;
   border: 1px solid #fff;
   margin-top: 30px;
   color: #fff;
   text-transform: uppercase;
   font-family: 'Roboto', sans-serif;
   font-weight: 300;
   -webkit-transition: background ease-out 500ms;
   -moz-transition: background ease-out 500ms;
   -o-transition: background ease-out 500ms;
@@ skipping 934 matching lines @@
     border-bottom-right-radius: 0;
     border-bottom-left-radius: 0;
   }
 
   .btn-group-responsive > .btn-group:last-child:not(:first-child) > .btn {
     border-radius: 6px;
     border-top-right-radius: 0;
     border-top-left-radius: 0;
   }
 }