change text color in Github header dashboard "Learn Git and Github without any code!"

[kartiksinghparmar]

.intro-shelf {
    margin-top: 0;
    color: rgba(27,31,35,.85);
    background-image: linear-gradient(180deg,hsla(0,0%,100%,0) 60%,#fff),linear-gradient(70deg,#dbedff 32%,#ebfff0);
    border-bottom: #fff;
}