This theme is a specialisation of the generic css framework: InvisCSS.
Theme demos are available here.
You can install this theme from npm using:
npm install inviscss-ultra-blue
And then include the css and js in your project:
<link rel="stylesheet" href="node_modules/inviscss-ultra-blue/css/inviscss-ultra-blue.min.css" media="all" type="text/css" />
<script src="node_modules/inviscss-ultra-blue/js/inviscss.min.js" type="text/javascript"></script>
You can use the NPM CDN (unpkg.com) directly, without any installation whatsoever:
<link rel="stylesheet" href="https://unpkg.com/inviscss-ultra-blue/css/inviscss-ultra-blue.min.css" media="all" type="text/css" />
<script src="https://unpkg.com/inviscss-ultra-blue" type="text/javascript"></script>
Rather than using npm, or it's CDN, you can download the latest inviscss-ultra-blue-xxx.zip from github.com/cmroanirgo/inviscss.
Then include the css and js directly into your project:
<link rel="stylesheet" href="css/inviscss-ultra-blue.min.css" media="all" type="text/css" />
<script src="js/inviscss.min.js" type="text/javascript"></script>
Both installation versions also include the original .less source files, if you wish to build/ integrate with other systems. You will need to run npm install in order to bring in the base InvisCSS project (and its dependencies), but this is not needed if using the provided css and js (and font) files.