How to set size of SVG image in :before pseudo- class ?

In CSS, when incorporating SVG images within pseudo-classes such as ::before or ::after and adjusting their size, several approaches are available. Below are the specific steps and examples:

Method 1: Set Size Directly in SVG Code

If you can directly modify the SVG code, you can set the size by specifying values in the width and height attributes of the SVG. Subsequently, embed this SVG code as Base64 or directly within CSS.

Example:

For instance, consider a simple SVG image; you can set it as follows in the SVG file:

xml
<svg width="30px" height="30px" viewBox="0 0 24 24" xmlns="http://www.w3.org/2000/svg">
    <!-- SVG content -->
</svg>

Then convert it to Base64 encoding and use it in CSS:

css
.element::before {
    content: "";
    display: block;
    width: 30px;  /* Can be adjusted, but it's recommended to match the internal SVG size */
    height: 30px;
    background-image: url("data:image/svg+xml;base64,..."); /* Base64-encoded SVG */
    background-size: contain;
}

Method 2: Control Size Using CSS Background Properties

If you lack the ability to modify the SVG file directly or if you source the SVG from a URL, you can leverage the CSS background-size property to control the SVG image's size.

Example:

css
.element::before {
    content: "";
    display: block;
    width: 50px;  /* Set the pseudo-element's width */
    height: 50px; /* Set the pseudo-element's height */
    background-image: url("path/to/your/image.svg"); /* Path to the SVG file */
    background-size: cover; /* Or use specific dimensions, such as '30px 30px' */
    background-repeat: no-repeat;
    background-position: center;
}

This method allows you to control the display size of the SVG within pseudo-classes without modifying the SVG file itself.

Summary

Both methods can be employed to incorporate and adjust SVG images within pseudo-classes, with the choice depending on your level of control over the SVG file and specific requirements. If frequent size adjustments are required or if the same image is used in multiple places with different sizes, the second method may be more flexible. If high performance is a critical requirement, directly modifying the SVG file and embedding it as Base64 may be more efficient.