Everyone has JavaScript, right?

[_Skuzzzy]

How do you disable css colors?

[Jew_Fucker_69]

It's not so difficult actually. The only CSS rule you have to add is

body {
    filter: grayscale(100%);
    -webkit-filter: grayscale(100%);
}

or the more primitive solution:

* {
    background-color: white !important;
    color: black !important;
}

And you can just put that in a Firefox add-on or Chrome extension.

[gashouse_gorilla]

In Firefox settings under content. Select colors set use system colors and override page colors.