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![Abraham Prieto](https://secure.gravatar.com/avatar/c56e716356c3e165cfeaa8309b89b9a2?s=96&d=https%3A%2F%2Fecs-static.teamtreehouse.com%2Fassets%2Fcontent%2Fdefault_avatar-445fbbabfc8dc9188fb5967fe43322ee0c3e0dd1e10f378bf8343784af5a13eb.webp&r=pg)
Abraham Prieto
4,469 Points.no-flexbox
Hi, I dont understand something you put the rule .no-flexbox in the style.css, but you didn't put the selector anywhere in the HTML.
2 Answers
![Andre Romano](https://uploads.teamtreehouse.com/production/profile-photos/1112732/micro_1240457_541278705944813_1386680402_n.jpg)
Andre Romano
8,809 PointsHey its probably for use with Modernizr, http://modernizr.com/ , it adds those classes through javascript when the page loads.
That one in particular gets used when the browser doesnt support FlexBox, so if your design relies on FlexBox you can target that .no-flexbox class and fix the styling for old browsers.
![Abraham Prieto](https://secure.gravatar.com/avatar/c56e716356c3e165cfeaa8309b89b9a2?s=96&d=https%3A%2F%2Fecs-static.teamtreehouse.com%2Fassets%2Fcontent%2Fdefault_avatar-445fbbabfc8dc9188fb5967fe43322ee0c3e0dd1e10f378bf8343784af5a13eb.webp&r=pg)
Abraham Prieto
4,469 PointsThanks for answer, you mind that .no-flexbox rule target to js of the modernizr?