Hello,

Try to use the code below to change the text color of the search:

.wd-header-search-form .searchform .s {
    color: red;
}

As for the menu, navigate to Theme Settings -> Typography -> Advanced and create such rule that is related to the menu:https://take.ms/DAqKF then change the color in the appropriate field here: https://take.ms/ds8Gz

Kind Regards