CSS Backgrounds
The CSS background properties are used to define the background effects for elements.
In these chapters, you will learn about the following CSS background properties:
- background-color
- background-image
- background-repeat
- background-attachment
- background-position
CSS Backgrounds-color
The background-color property specifies the background color of an element.
Example
<!DOCTYPE html>
<html>
<head>
<style>
body {
background-color: lightblue;
}
</style>
</head>
<body>
<h1>Hello World!</h1>
<p>This page has a light blue background color!</p>
</body>
</html>
With CSS, a color is most often specified by:
- a valid color name - like "red"
- a HEX value - like "#ff0000"
- an RGB value - like "rgb(255,0,0)"
Look at CSS Color Values for a complete list of possible color values.
Other Elements
You can set the background color for any HTML elements:
Example
Here, the <h1>, <p>, and <div> elements will have different background colors:
<!DOCTYPE html>
<html>
<head>
<style>
h1 {
background-color: green;
}
div {
background-color: lightblue;
}
p {
background-color: yellow;
}
</style>
</head>
<body>
<h1>CSS background-color example!</h1>
<div>
This is a text inside a div element.
<p>This paragraph has its own background color.</p>
We are still in the div element.
</div>
</body>
</html>
Opacity / Transparency
The opacity property specifies the
opacity/transparency of an element. It can take a value from 0.0 - 1.0.
The lower value, the more transparent:
<!DOCTYPE html>
<html>
<head>
<style>
div {
background-color: green;
}
div.first {
opacity: 0.1;
}
div.second {
opacity: 0.3;
}
div.third {
opacity: 0.6;
}
</style>
</head>
<body>
<h1>Transparent Box</h1>
<p>When using the opacity property to add transparency to the background of an element, all of its child elements become transparent as well. This can make the text inside a fully transparent element hard to read:</p>
<div class="first">
<h1>opacity 0.1</h1>
</div>
<div class="second">
<h1>opacity 0.3</h1>
</div>
<div class="third">
<h1>opacity 0.6</h1>
</div>
<div>
<h1>opacity 1 (default)</h1>
</div>
</body>
</html>
Transparency using RGBA
If you do not want to apply opacity to child elements, like in our example above, use RGBA color values. The following example sets the opacity for the background color and not the text:
<!DOCTYPE html>
<html>
<head>
<style>
div {
background: rgb(0, 128, 0);
}
div.first {
background: rgba(0, 128, 0, 0.1);
}
div.second {
background: rgba(0, 128, 0, 0.3);
}
div.third {
background: rgba(0, 128, 0, 0.6);
}
</style>
</head>
<body>
<h1>Transparent Box</h1>
<p>With opacity:</p>
<div style="opacity:0.1;">
<h1>10% opacity</h1>
</div>
<div style="opacity:0.3;">
<h1>30% opacity</h1>
</div>
<div style="opacity:0.6;">
<h1>60% opacity</h1>
</div>
<div>
<h1>opacity 1</h1>
</div>
<p>With RGBA color values:</p>
<div class="first">
<h1>10% opacity</h1>
</div>
<div class="second">
<h1>30% opacity</h1>
</div>
<div class="third">
<h1>60% opacity</h1>
</div>
<div>
<h1>default</h1>
</div>
<p>Notice how the text gets transparent as well as the background color when using the opacity property.</p>
</body>
</html>
CSS background-image
The background-image property specifies an image to use as the background of an element.
By default, the image is repeated so it covers the entire element.
<!DOCTYPE html>
<html>
<head>
<style>
body {
background-image: url("paper.gif");
}
</style>
</head>
<body>
<h1>Hello World!</h1>
<p>This page has an image as the background!</p>
</body>
</html>
The background image can also be set for specific elements, like the <p> element:
<!DOCTYPE html>
<html>
<head>
<style>
p {
background-image: url("paper.gif");
}
</style>
</head>
<body>
<h1>Hello World!</h1>
<p>This paragraph has an image as the background!</p>
</body>
</html>
