How to change transparency in css

CSS is a language used for web design and layout. It can change the size, color, position, border and other attributes of elements. And one of the common needs is to change the transparency of an element.

There are two common ways to change transparency: one is to use rgba color value, the fourth parameter represents transparency, the value range is 0 to 1; the other is to use the opacity attribute, the value range is also is 0 to 1. Next, these two methods and their usage scenarios will be introduced in detail.

1. Use rgba color values

Using rgba color values ​​can directly change the transparency of elements without affecting other styles, such as borders and shadows. This method is suitable for scenarios where other styles do not need to be changed.

Code example:

.element {
  background-color: rgba(255, 0, 0, 0.5);  /* 红色半透明 */
  border: 1px solid #000;
  box-shadow: 2px 2px #ccc;
}

Effect display:

##Use opacity attribute

opacity The property refers to the transparency of the entire element, that is, the transparency of the element and its contents. This means that if a parent element uses the opacity attribute, its child elements will also inherit that transparency value. And this attribute will also change the color, border, shadow and other styles of the element. For example, if the opacity of an element is set to 0.5, the transparency of its color, border and shadow will also become 0.5.

Code example:

.parent {
  opacity: 0.5;
}

.child {
  background-color: #fff;
  border: 1px solid #000;
  box-shadow: 2px 2px #ccc;
}

Effect display:

##Usage scenario

3. The above two Both methods can change the transparency of elements, but they will have different effects in different scenarios. Generally speaking, if you only need to change the background color transparency of an element, it is recommended to use rgba color values, which can maintain the opacity of the border and shadow. If you need to change the transparency of an element and its content at the same time, you can use the opacity attribute.

For example, when designing a card, it is often necessary to make the card have a certain degree of transparency, so that it will look more beautiful. At this time, you can use the opacity attribute, as shown below:

.card {
  background-color: #fff;
  border-radius: 10px;
  box-shadow: 2px 2px 10px #ccc;
  opacity: 0.8;
}

Effect display:

##Summary

Changing the transparency of an element is a web design One of the common requirements in , can be achieved through rgba color value and opacity attribute. When using it, you need to choose the appropriate method according to the specific scenario. Among them, the rgba color value is more suitable for scenes where only the background color transparency is changed, while the opacity attribute is more suitable for scenes where the transparency of the element and its content is changed at the same time.

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