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 Basics (2014) Basic Layout box-sizing and max-width

What is the percentage value relative to?

.

3 Answers

Steven Parker
Steven Parker
231,236 Points

Percentage units in CSS are generally based on the size of the parent object, which could be considered a "container". For more details, see this MDN page on Percentage.

The browser window is a container, but it would not be the immediate parent of anything other than the "root" element.

.

Steven Parker
Steven Parker
231,236 Points

I think he mentions the browser because that's what he can easily change the size of. The "div" elements with the classes you mention are enclosed by the "body" element, which automatically fills the browser window. So those percentages would be based on the width of the "body".

.

Steven Parker
Steven Parker
231,236 Points

Percentages are relative to the parent container, and never to the body specifically. In this particular case, the body just happens to be the parent container.

.

Steven Parker
Steven Parker
231,236 Points

Unless I missed something in the video code, the element with the class "primary-content" is a div, and it is a direct child of the body element. There's no "parent container div".