curriculum/challenges/english/blocks/basic-css/bad87fee1348bd9aecf08806.md
Classes are reusable styles that can be added to HTML elements.
Here's an example CSS class declaration:
<style>
.blue-text {
color: blue;
}
</style>
You can see that we've created a CSS class called blue-text within the <style> tag. You can apply a class to an HTML element like this: <h2 class="blue-text">CatPhotoApp</h2>. Note that in your CSS style element, class names start with a period. In your HTML elements' class attribute, the class name does not include the period.
Inside your style element, change the h2 selector to .red-text and update the color's value from blue to red.
Give your h2 element the class attribute with a value of red-text.
Your h2 element should be red.
const h2Element = document.querySelector('h2');
const color = window.getComputedStyle(h2Element)['color'];
assert.strictEqual(color, 'rgb(255, 0, 0)');
Your h2 element should have the class red-text.
assert.isTrue(document.querySelector('h2').classList.contains('red-text'));
Your stylesheet should declare a red-text class and have its color set to red.
assert.match(__helpers.removeCssComments(code), /\.red-text\s*\{\s*color\s*:\s*red;?\s*\}/g);
You should not use inline style declarations like style="color: red" in your h2 element.
assert.notExists(document.querySelector('h2').getAttribute('style'));
<style>
h2 {
color: blue;
}
</style>
<h2>CatPhotoApp</h2>
<main>
<p>Click here to view more <a href="#">cat photos</a>.</p>
<a href="#"></a>
<div>
<p>Things cats love:</p>
<ul>
<li>catnip</li>
<li>laser pointers</li>
<li>lasagna</li>
</ul>
<p>Top 3 things cats hate:</p>
<ol>
<li>flea treatment</li>
<li>thunder</li>
<li>other cats</li>
</ol>
</div>
<form action="https://freecatphotoapp.com/submit-cat-photo">
<label><input type="radio" name="indoor-outdoor" checked> Indoor</label>
<label><input type="radio" name="indoor-outdoor"> Outdoor</label>
<label><input type="checkbox" name="personality" checked> Loving</label>
<label><input type="checkbox" name="personality"> Lazy</label>
<label><input type="checkbox" name="personality"> Energetic</label>
<input type="text" placeholder="cat photo URL" required>
<button type="submit">Submit</button>
</form>
</main>
<style>
.red-text {
color: red;
}
</style>
<h2 class="red-text">CatPhotoApp</h2>
<main>
<p>Click here to view more <a href="#">cat photos</a>.</p>
<a href="#"></a>
<div>
<p>Things cats love:</p>
<ul>
<li>catnip</li>
<li>laser pointers</li>
<li>lasagna</li>
</ul>
<p>Top 3 things cats hate:</p>
<ol>
<li>flea treatment</li>
<li>thunder</li>
<li>other cats</li>
</ol>
</div>
<form action="https://freecatphotoapp.com/submit-cat-photo">
<label><input type="radio" name="indoor-outdoor" checked> Indoor</label>
<label><input type="radio" name="indoor-outdoor"> Outdoor</label>
<label><input type="checkbox" name="personality" checked> Loving</label>
<label><input type="checkbox" name="personality"> Lazy</label>
<label><input type="checkbox" name="personality"> Energetic</label>
<input type="text" placeholder="cat photo URL" required>
<button type="submit">Submit</button>
</form>
</main>