Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

CSS CSS Flexbox Layout Building a Layout with Flexbox Creating a Two Column Layout with Flexbox

Why ."col can control the class of "primary col" and "secondary col" while not specifying the name?

As shown in the video, in the CSS stylesheet

    flex: 1;
  }```
controls both "primary col" and "secondary col"

Why is that?

Thanks a lot!

1 Answer

Steven Parker
Steven Parker
229,005 Points

The rule you are referring to has a selector of ".col", which matches anything that has the class of "col".

And both of these elements include "col" as one of their classes.

Oh I see, thanks for the prompt reply!