monkeytype/public/themes/matrix.css

:root {
    --bg-color: #000000;
    --main-color: #15ff00;
    --caret-color: #15ff00;
    --sub-color: #032700;
    --text-color: #adffa7;
    --error-color: #da3333;
    --error-extra-color: #791717;
    --colorful-error-color: #da3333;
    --colorful-error-extra-color: #791717;
}

#liveWpm, #timerNumber{
    color: white;
}