Why is it Impossible to Change Checkbox Color Regardless of Code Modifications?

Despite efforts to customize the background color of checkboxes through CSS, many users encounter a lack of visible changes. This issue has been prevalent in Firefox 29 and later.

Explanation

The inability to alter the checkbox color stems from a deliberate omission of this functionality in HTML. Checkboxes and radio buttons are regarded as "native" form elements, meaning their appearance is governed by the browser rather than CSS rules. Browsers prioritize consistency in the user interface, and thus, they enforce the default visual properties for these elements.

Solution

To overcome this limitation and customize the checkbox appearance, consider utilizing the following CSS property:

accent-color

By setting this property, you gain control over the accent color applied to the checkbox, which encompasses the check mark and any accompanying background. Here's an example:

#cb1 {
  accent-color: #9b59b6; /* Change the color of the check mark within checkbox #cb1 to blue */
}

Demonstration

See the demo below to witness the successful modification of checkbox colors using the accent-color property:

#cb1 {
  accent-color: #9b59b6;
}

#cb2 {
  accent-color: #34495e;
}

#cb3 {
  accent-color: #e74c3c;
}