This issue is regarding UI design. The "sign in" and "Create account" link was changed to black for some reason in the recently updated master's repository. Flukeout just wanted me to change the colour of the text to the original which was white colour.
This was due to a recent changes to master's repo in github. Of course, this was unintentional!
To solve this issue, I used the Firefox inspector to find which html selector was being used. Then I was able to locate proper CSS page. Because I had experience with using CSS from previous bug that I worked on, I thought to myself, "oh this bug is gonna be super easy" - I was dead wrong.
It looked simple, but for someone who doesn't have good knowledge of HTML and how selectors work it was still a bit difficult. Or maybe I was thinking too simple. I thought all I need to do was to nest the selectors in one another but it did not work for me because according to Google, opacity cannot be overwritten.
Another thing I tried to do was change the opacity of navbar-anonymous selector, which encapsulated the entire top right text box, but since in thimble, the "sign in" and "create account" links are within the selector, they also changed to 0.65 opacity.
flukeout was able to give me hand with this one. He told me to look at the entire navbar, instead of just looking at the section - which is what I did. There, it was missing a "colour" in that element. With this, I was able to fix the issue and commit the changes.