[<style type="text/css">
/*framework*/
* {
    max-width: 100%;
}
img {
    display: block;
    margin: auto;
}
body {
    font: normal normal 14px Arial;
    background: #f1f1f1;
}
</style>]

How to add?

Every block quote with [ at the beginning and ] at the end will become a code box