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![Erik Nuber](https://secure.gravatar.com/avatar/77da1f177f7c7c2803850f8145082bed?s=96&d=https%3A%2F%2Fecs-static.teamtreehouse.com%2Fassets%2Fcontent%2Fdefault_avatar-445fbbabfc8dc9188fb5967fe43322ee0c3e0dd1e10f378bf8343784af5a13eb.webp&r=pg)
Erik Nuber
20,629 Points.no-flexbox class when creating fallback CSS.
Would like to know why this is being used and, how it actually is working within the CSS when it doesn't seem to reference a class in either the HTML or the modernizr.js file.
We included a Modernizr.js file and linked it via a script but otherwise, there isn't a class for "no."
1 Answer
![christophe Bonge](https://uploads.teamtreehouse.com/production/profile-photos/2029572/micro_Captain_A.png)
christophe Bonge
6,618 Pointshi, after linked modernizr.js to your html file, if you emulate this file in IE 9 ( which doesn't support flexbox ) you will see in the IE9 dev tools a class="no-flexbox" in your HTML element . This is the class you will use to make a fallback for IE 9.