Hi @Shobhit
The code provided by @Katie_W should work but still you are facing issues, try identifying the elements of that part of the survey which is still unchanged and then add them in the same code provided. Please see below code for your reference.
.Skin .QuestionText
{
color: black;!important
}
.Skin .QuestionBody
{
color: black;!important
}
.Skin .QuestionOuter
{
color: black !important;
}
.Skin .Matrix table td,
.Skin .Matrix table th {
color: black !important;
}
.Skin .EndOfSurvey,
.Skin .Q_lang {
color: black !important;
}
Here, Matrix refers to the matrix question and similarly the End of Survey message that I have in my survey.
Hope it helps!