CSS
Background shorthand
Write all background properties in one line with the background shorthand.
The background shorthand
The background shorthand gathers several background properties on one line. background: #1a1a2e url("/images/hero.jpg") no-repeat center top; sets color, image, repeat and position in a single declaration.
When you use the shorthand, any property you leave out resets to its default. So if you set background-color first and then write background, the color may vanish. Use the shorthand on its own, or last.
background-size
background-size sets the image's size inside the surface. You can give pixels with two values like 200px 100px, or use a keyword.
cover scales the image to fill the box completely, keeping the aspect ratio; any overflow is clipped. contain shows the whole image, leaving some empty space. For a hero section you usually pick cover.
background-attachment
background-attachment controls how the image behaves when the page scrolls. The default is scroll; the image scrolls with the element.
With fixed the image is locked to the viewport; the page scrolls over it, creating a parallax-like effect. In a hero section, fixed makes the image feel still. local scrolls the image with the element's own content.
Exercise Set up the .banner background
Add a .banner class selector. Set its background shorthand to #1a1a2e url("/images/banner.jpg") no-repeat center top, its background-size property to cover, and its background-attachment property to fixed.
Show example solution
/* set up the .banner background */
.banner {
background: #1a1a2e url("/images/banner.jpg") no-repeat center top;
background-size: cover;
background-attachment: fixed;
}
Test yourself
-
Which is a valid background shorthand?
- background-image: url("/x.jpg")
- background-color: #1a1a2e
- background: #1a1a2e url("/x.jpg") no-repeat center top
- background-position: center top
Show answer
background: #1a1a2e url("/x.jpg") no-repeat center top — Correct. The background shorthand can give color, image, repeat and position in one declaration.
-
Write the size value so the hero image fills the box
.hero {
background: url("/images/hero.jpg") no-repeat center top;
background-size: ____;
}
Show answer
.hero {
background: url("/images/hero.jpg") no-repeat center top;
background-size: cover;
}
-
Match each size value to its effect
- cover
- Fills the box, clips overflow
- contain
- Shows whole image, may leave space
- 200px 100px
- Two dimensions in pixels
- auto
- Keeps the original size
Next lesson: Summary - Hero section
