I am having trouble completing the challenge for the "Create and Edit Lightning Components" module of the "Lightning Components Basics" trail. Here is the challenge:

Create a camping component that contains a campingHeader and a campingList component.
    The campingList component contains an ordered list of camping supplies that include Bug Spray, Bear Repellant, and Goat Food.
    The campingHeader component contains an H1 heading style with a font size of 18 points and displays 'Camping List'.

Here is my code:

camping.cmp

<aura:component >   
    <c:campingHeader/>
    <c:campingList/>
</aura:component>

campingHeader.cmp

<aura:component >
    <H1>Camping List</H1>
</aura:component>

campingHeader.css

.THIS {
}

H1.THIS {
    font-size: 18px;
}

campingList.cmp

<aura:component >
    <aura:attribute name="campingSupplies" type="List" default="['Bear Repellant', 'Bug Spray', 'Goat Food']" />
</aura:component>

When I check the challenge, I get the error message:

Challenge Not yet complete... here's what's wrong:
The component is not using the correct font size.

Any help is greatly appreciated.

Hi all,
I have an issue when I come to open my developer console. It opens and start to load but it quickly minimizes, showing a "loading..." text.
After that, the developer console's window freezes completely, allowing me only to close it. Same happens to the window I used to open the developer console. 
I find a solution here http://salesforce.stackexchange.com/questions/80453/developer-console-is-not-loading but I don't have enough time to switch my workspace.
I tried cleaning the browser data but nothing changed. I can also use the developer console of other salesforce accounts, so it seems it only happens with my account.

And I have another issue, I don't know if it's related or not, I'm posting it here just in case it is and it helps to see the problem.
As I couln't continue using the default developer console, I downloaded Welkin Suite, but when I build the solution, I keep getting an error that says "file has pending server changes. Please pull first", which it doesn't fix after a pull. When I'm not getting that error I get strage errors like "The attribute “(...)” was not found on the COMPONENT markup://(...): Origin"

Thanks in advance to anyone who can help me solving this!