HTML interface for Google Sheets:

(see examples in “script tests”)

Using Bootstrap:

make layouts here

it appears (?) you need https to load external files?

before </head>: <link rel=“stylesheet” href=“https://maxcdn.bootstrapcdn.com/bootstrap/3.3.2/css/bootstrap.min.css”>

before </body>:

</body>

reference: http://stackoverflow.com/questions/27863416/can-bootstrap-js-be-used-in-gas-google-apps-script