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) Understanding Values and Units Em and Rem Units

Robbie Singh
Robbie Singh
3,675 Points

Confusing Challenge

The em-based font-size values for .title and h1 are relative to their parent header's font-size value. This causes a compounding issue that makes their font size values larger than the desired values.

Replace the em units of .title and h1 with a unit that is relative to the root element of the page.

Not sure how to do go about this one.

/* Complete the challenge by writing CSS below */

header {
  font-size: 1.8em;

.title {
  font-size: 1.4em;

h1 {
  font-size: 1.2em;
<!DOCTYPE html>
    <title>Lake Tahoe</title>
    <link rel="stylesheet" href="page.css">
    <link rel="stylesheet" href="style.css">
      <span class="title">Journey through the Sierra Nevada Mountains</span>
      <h1>Lake Tahoe, California</h1>
    <div class="main-content">
        Lake Tahoe is one of the most breathtaking attractions located in California. It's home to a number of ski resorts, summer outdoor recreation, and tourist attractions. Snow and skiing are a significant part of the area's reputation.
      <a href="#">Find out more</a>
      <h2>Check out all the Wildlife</h2>
        As spawning season approaches, the fish acquire a humpback and protuberant jaw. After spawning, they die and their carcasses provide a feast for gatherings of mink, bears, and Bald eagles.
      <a href="#">See the Wildlife</a>
      <h3>From Tents to Resorts</h3>
        Lake Tahoe is full of wonderful places to stay. You have the ability to sleep in the outdoors in a tent, or relax like a king at a five star resort. Here are our top three resorts:
      <p>All rights reserved to the state of <a href="#">California</a>.</p>
      <a href="#top">Back to top &raquo;</a>

4 Answers

Guil Hernandez
Guil Hernandez
Treehouse Teacher

Hi Robbie Singh,

I cover just that in this videoโ€”it's the unit the video is about. :)

Robbie Singh
Robbie Singh
3,675 Points

Haha, wow. I did not expect you to be watching this! Rem Okay that makes sense! Thanks Guil for your help and teachings.

Hi Robbie,

The challenge starts by using em units on the .title and h1 which are relative to the parent element.

A rem is root em (relative to the root element) and so it's just a case of changing the styles to account for this.

Here's the unit info from w3schools which should hopefully help.

EDIT: Was attempting to give an explanation behind the answer but reworded so not as obvious... :)


put "rem" instead of "em"

14,636 Points

The answer is in the title of the challenge bro...

You're using em's as your value in your code. That sizes the font in relation to the parent element, you want the font to be relative to the ROOT element...

So... what's the fix?

edit: nevermind...answers spoonfed again.

Robbie Singh
Robbie Singh
3,675 Points

rems are the answer they do not cause compounding issues. Overcomplicating simple! Thanks.