How to Animate Details Element using CSS ?

Last Updated : 06 Dec, 2022

Details Element is an element in HTML to create a Dialog box with some summary that can open or close. In this article, you will understand to animate the details element using CSS.

Syntax:

<details [open]>
   <summary> ... </summary>
</details>

open: By adding this attribute, we can set the Dialog box to be opened by default.

Example 1: In this example, we will look at how the details element works without any styling.

HTML

<!DOCTYPE html>
<html>

<head>
    <title>Page Title</title>
</head>

<body>
    <h1 style="color:green">GeeksForGeeks</h1>
    <h3>How to Animate the Details Element using CSS ?</h3>
    <details open>
        <summary>Hello GFG</summary>
        About this site ...
    </details>
</body>

</html>

Output:

Amination on Details Element: Now we need to animate it to close/open. HTML provides its own default feature to this element by which it can close or open the content, but it's not much responsive and hence we can use CSS to make it look attractive.

It consists of an arrow to open and close which we can animate using CSS. On the click of the arrow, the details element expands. Below is the approach to animate the arrow of the details element.

Approach 1: Now, we will animate the details element with CSS. You can animate the arrow at the summary area as follows:

Design your own arrow with the CSS border and pseudo element selector. Below I am creating a green color arrow using: :before (You can also use: :after)
Remove the default black color arrow by making the summary display as block
Animate the newly created arrow when it is open. Using the below code

details[open] > element_to_be_animated { ... }

Example: In this example, we are making an arrow to rotate by 90^o below using the above approach. Using summary I am selecting the details summary element and using ::before I am designing the arrow

By making the summary display as a block I am removing the default arrow from the details element

HTML

<html>

<head>
    <title>Page Title</title>
    <style>
        /* For animating the arrow on 
           click of details element */
        details[open]>summary:before {
            transform: rotate(90deg);
        }

        /* Removing the default arrow */
        summary {
            display: block;
            position: relative;
            font-size: 20px;
            left: 20px;
        }

        /* designing the arrow */
        summary:before {
            content: '';
            border: 10px solid;
            border-color: transparent transparent transparent green;
            position: absolute;
            left: -20px;
            top: 2px;
            transition: all .4s;
        }
    </style>
</head>

<body>
    <h1 style="color:green">GeeksforGeeks</h1>
    <h3>How to Animate the Details Element using CSS ?</h3>
    <details>
        <summary>GFG</summary>
        <h1>Hello GeekforGeeks</h1>
    </details>
</body>

</html>

Output:

Approach 2: In this approach, we will add a hover effect on the details content

Example: In this example, we are making the details element more responsive. Here the content's font size also increases responsively when it opens and gets hovered.