Firefox 94 and newer
Just change the input's background color in your css:
input:autofill {
background: #fff; /* or any other */
}
If you wish to remove the autofill background only in your Firefox browser, set layout.css.autofill.background
to false
in about:config
.
Firefox 67 (2019-05-21) - 94 (2021-11-02; excluding)
Add this to your css:
input {
filter: none;
}
Why? At the bottom of view-source:resource://gre-resources/forms.css
we can see this:
:-moz-autofill, :-moz-autofill-preview {
filter: grayscale(21%) brightness(88%) contrast(161%) invert(10%) sepia(40%) saturate(206%);
}
And that is the cause of the yellow autofill background color.